Travelling from Germany to the Paris International Exposition, in the summer of 1937, Leni Riefenstahl went under an assumed name. She had no desire to confront reporters. In Paris, she won the fair’s gold medal for a film she had directed, a documentary-style celebration of the Nazi Party congress three years earlier. Yet she was also forced to defend herself, in interviews, not against her Nazi ties but against the swirling rumors that she had fallen into disgrace with the leaders of the Reich. Was it true that Goebbels had repudiated her? Were some upper-echelon Nazis unhappy that a woman wielded so much power? On her way back to Berlin, exhausted, she stopped off in Berchtesgaden, where she was escorted to Adolf Hitler’s mountain retreat, so that she could describe her trip to the one man whose support for her was absolute.

Hitler had bypassed all the sanctioned Party hacks to hire Riefenstahl to direct her first official Nazi film, in 1933, and he had provided the title for the second, “Triumph of the Will,” so recently triumphant in Paris. He was deeply interested in movies, and screened them often in his home. Riefenstahl, ushered into an entrance hall, found herself watching a film in progress; she recognized Marlene Dietrich’s face before the Führer appeared and took her off for coffee on the terrace. Hitler’s choice of a Dietrich film might have seemed curious, since his ministers had long campaigned to destroy her reputation. Although she was the greatest movie star that Germany had ever produced, Dietrich refused to work in Germany. And it was no longer possible to pretend that her choices were not political. A few months before Riefenstahl’s visit, Dietrich announced that she had applied for American citizenship, posing for reporters outside the federal building in Los Angeles with one leg propped on the running board of her chauffeured Cadillac, and saying things like “America has been good to me.” The Nazi tabloid Der Stürmer informed its readers that Dietrich’s years among “the film Jews of Hollywood” had rendered her “wholly un-German”—which did not keep Hitler from very much wanting her back.

Two beautiful and ambitious Berliners, born just eight months apart—Marie Magdalene Dietrich, on December 27, 1901; Bertha Helene Amalie Riefenstahl, on August 22, 1902—both bound to shape the fantasies and touch the histories of their time. Two girls growing up amid the fear and chaos of the Great War, two artists committed to impossible ideals of physical beauty, two women who became embodiments not only of the opposing sides of the next war but, for many, of opposing forces in the human soul. They scarcely knew each other, although during the late twenties they were such close neighbors that Riefenstahl claimed she could see into Dietrich’s apartment windows.

It is unlikely that Dietrich would have looked back. There are a few photographs showing the two of them at the Berlin Press Ball in early 1930: Dietrich, on the brink of the huge success of “The Blue Angel,” smiles and clowns with ease, a jaunty cigarette holder clamped between her lips, the broad planes of her face soaking up the camera’s light and affection; Riefenstahl, then a well-known film actress, too, stands by shy and awkward, self-consciously eclipsed. Decades later, Riefenstahl recorded several anecdotes about Dietrich in her memoirs. Dietrich, in a sketchier memoir of her own, had nothing to say about Riefenstahl. Dietrich’s daughter, however, wrote of hearing a conversation in the mid-thirties about Jewish actors who had been thrown out of Germany. “Soon they won’t have any talent left for their big ‘cultural Reich,’ ” Dietrich said, “except, of course, that terrible Riefenstahl and Emil Jannings. They will stay, and those two ‘well-poisoners’—the Nazis deserve!”

The two women never saw each other again after 1930, when Dietrich left Germany, nor did they write or speak or maintain more than a few acquaintances in common. Karin Wieland’s dual biography “Dietrich & Riefenstahl: Hollywood, Berlin, and a Century in Two Lives” (Liveright), translated from the German by Shelley Frisch, gets around these problems largely by ignoring them. The book’s alternating sections keep their subjects separate, except on a few inevitable occasions—say, when Riefenstahl received a phone call informing her that Dietrich had won the role that Riefenstahl coveted in “The Blue Angel,” and was so upset that she sent her dinner guest home without his promised goulash. This isn’t the first time the story has been told; it originates in Steven Bach’s 1992 biography of Dietrich. Bach, who interviewed Riefenstahl’s dinner guest, a film-magazine editor, observes that Riefenstahl generally did not audition but, rather, dined.

One could gain more detail about both women by reading two full-scale biographies: Bach has also written an excellent book on Riefenstahl, as has Jürgen Trimborn. Wieland is shrewd, though, about her subjects and has done serious work in German archives, producing documents—a reassuring letter from Riefenstahl to Albert Speer, in 1944, predicting a “great turning point in this war”; an unpublished memoir by Riefenstahl’s inconveniently Jewish early lover-financier; several Dietrich letters—that give her book credibility, texture, and unending interest. This is the story of two glamorous women whose achievements in another time might have been no more substantial than the images on a screen but who assumed real-life roles with the highest historical stakes. However inscrutable human conduct, it is difficult not to search these lives for insight into some of the modern era’s most difficult questions, about illusion and mass intoxication, art and truth, courage and capitulation.

Could their very different childhoods tell us something about the choices they ultimately made? Consider what it meant to be the product of a Prussian military family, a girl whose father died before she was old enough to remember him beyond the vague impressions she listed later on as “tall, imposing stature, leather smell, shining boots, a riding whip, horses”—a father whose absence prompted her need for a “masculine model,” as she saw it, and whose mother raised her like “a kindly general,” providing every sort of lesson (violin, piano, English) on a widow’s meagre earnings. It would be easy to see here someone who came to welcome Hitler’s leather-costumed militarism, yet this is an outline of Dietrich’s childhood and the forces that she felt had made her who she was. Riefenstahl grew up in a working-class family on the rise; her mother was a seamstress, her father was a plumber who built up a successful business and was the dominating figure of her early life. Dietrich had an older sister, Riefenstahl a younger brother, both of whom were the “obedient” children in the family and pleased their parents by following conventional paths. Neither the bourgeois widow nor the ambitious plumber could accept the notion that a well-brought-up German girl would ever appear on the stage.

It seemed a particularly far-fetched dream in wartime. The war had begun just as the girls were entering adolescence—as Marie Magdalene decided she would be called by the more stage-worthy Marlene. In her diary, she wrote about attending a “real cinema” but also about the death of her uncle Otto at the front: “Shot in the neck on the fourth of December. Everybody’s crying.” Her mother remarried, and her stepfather, too, was killed at the front; by sixteen, she was mourning her “golden youth.” Later, Dietrich recalled the meals made entirely of turnips, the cold of those years without fuel, and the continuing sacrifice of men she knew that brought her “face-to-face with the war.”

No such events or feelings seem to have touched Riefenstahl, who was not from a military family and suffered no personal losses. She lived in a “cloud of unknowing,” or so she claimed in her memoirs, which were set on projecting the image of an artist too immersed in her work to notice her surroundings. “My mind was turned in on a tiny exclusive world,” she wrote, referring to the long hours of dance lessons that she had begun to take without her father’s knowledge. Her determination was formidable. But, at her own best evaluation, she was a woman who never came face to face with anything, because the only face she saw was her own.

By the early twenties, both young women were on the stage, having overcome parental objections by sidestepping the floozy connotations of such a career. Dietrich took lessons at the illustrious Max Reinhardt School, and performed in tiny roles in Reinhardt’s classic repertoire. Riefenstahl took to the elevated styles of modern dance then popular in Berlin, cultivating the aura of a barefoot priestess, even when costumed in a silver lamé leotard under transparent (but ethereally floating) chiffon. She also found a backer: the young Romanian-born Jewish banker Harry Sokal, who wanted to marry her but agreed instead to rent large theatres for her solo concerts, hire musicians, and take out ads. She made her professional début in 1923 and was well received, but in less than a year a knee injury brought her career to a halt. She was on her way to a doctor, utterly depressed, when she saw a poster for a film titled “Mountain of Destiny,” featuring a man poised between steep walls of mountain rock. She skipped her appointment and went to see the movie. It proved to be one of the two great epiphanies of her life.

“Mountain films” were a genre exclusive to Germany. Flourishing in the twenties and thirties, they began as sports documentaries and turned into quasi-mystical adventures played out on icy peaks by supremely heroic skiers or mountain climbers. The pioneer director of these films was Arnold Fanck, a geologist who’d taught himself to use a movie camera, a technical innovator with no studio connections. Riefenstahl was enthralled by “Mountain of Destiny,” and was determined to be part of Fanck’s next venture, even though the only mountains she’d ever seen were on postcards. Fanck responded to her overture by quickly writing a screenplay just for her; it may have helped that Harry Sokal had agreed to pay a quarter of the film’s costs.

“Here’s the deal: we call the shots when you’re young, you call the shots when we’re old, and everything in between is a non-stop battle for control.”

“The Holy Mountain” opened with a closeup of Riefenstahl’s face and continued with a sequence of her dancing on a shelf of rock above the sea: she was a joyous nymph, a child of nature, and a brand-new movie star. The film, which centered on the rivalry between two mountaineering friends for the dancer’s favor, was Fanck’s biggest success so far. Riefenstahl later revealed that Hitler had admired her “dance on the sea,” but even at the time of the film’s release, in 1926, it was interpreted politically, by critics on both the disapproving left (“Obtrusive propaganda for noble-blond, high-altitude humanity”) and the welcoming right (“This way, German film, to the holy mountain of your rebirth and that of the German people!”).

Riefenstahl went on to make several more mountain films with Fanck. She became adept at skiing and climbing, and did all her own stunts, often in freezing weather. She was hauled up on ropes through a real avalanche; she crossed a treacherous chasm on a wobbly ladder laid end to end. She was an early action heroine. But she wanted something more—to make a film with an esteemed director, with a real studio, indoors. In August, 1929, the renowned Josef von Sternberg took a few months off from Hollywood to make a movie in Berlin, and word went out that he needed a young female star. Riefenstahl did some assiduous dining with Sternberg; later on, to save face, she claimed that it was she who had told him all about Marlene Dietrich.

“The Blue Angel” was meant to be a vehicle for the German silent-film star Emil Jannings, who had also had a big success in Hollywood—he had just won the first Academy Award for Best Actor—but, with limited English, was returning to Berlin to make his first official talkie. Produced by the biggest German studio, Ufa, with Paramount’s coöperation, the film was to be shot in both a German and an English version. Sternberg first saw Dietrich that September, in a musical, and was struck by her “cold disdain” for the buffoonery around her. Neither Jannings nor the producer wanted her: at twenty-seven, she had long since traded the classics for a string of stage and film roles as a glamour girl, and she seemed already somewhat past her prime: early comparisons to Garbo had become criticism of her “slavish imitation” of Hollywood’s reigning star.

Sternberg’s film, based on the novel “Professor Unrat,” by Heinrich Mann, was the story of an old and priggish teacher who falls for a small-time cabaret singer. The professor was the central role, the girl merely the agent of his destruction. But Sternberg had changed the title to the name of the cabaret—and, by intimation, to the girl—in the hope of turning the emphasis around. When Dietrich stepped onstage, he knew the idea would work.

At ease with her sexual powers, wryly funny, unflinchingly amoral, Lola Lola, the cabaret singer of “The Blue Angel,” was also a new sort of woman on the screen. Dietrich wasn’t yet the goddess she would become: she’s rough around the edges, a bit thick in the waist, less polished and more natural than she ever was again. But in her white satin top hat and her exposed garters, flashing her legs while singing “Falling in Love Again”—“What’s a girl to do? I can’t help it”—she was the essence of Weimar sexual sophistication, the imperturbable center of the night world that Sternberg built around her. Seedy but vital, that world was filled with magical detail: a chorus of chubby overage showgirls, a live bear led calmly through Lola Lola’s dressing room, a mysteriously sad and silent clown overlooking all. Nothing could be further from Riefenstahl’s mountain films. Even Sternberg’s city alleyways are painted scenery; only the psychology of the main characters seems entirely real. The Nazi Party condemned “The Blue Angel,” if to little effect. But Dietrich was gone by then, in any case. She read the first German reviews (“Fascinating as no woman has ever been before in film”) on shipboard, on her way to Hollywood, where Sternberg waited to complete her transformation.

“I am Marlene,” he said later, and she agreed. She inscribed a photograph that she gave him, a year after her arrival, “To my creator, from his creation.” He was in love with her, but even more in love with the image of her that he projected on the screen. She was not in love with him; after an initial romance, he made love to her only through the camera, a fact that may have contributed to the allure that his lens discovered in her. Both were married, but it didn’t matter. Sternberg’s wife, in a rage over his obsession, sued for divorce. Dietrich had left her husband and small daughter in Berlin; she later collected the daughter, and although she never divorced her husband—he remained a friend, an adviser, and a dependent for decades—he did not interfere with her numberless affairs.

Sternberg was small and dark and Jewish; the “von” in his name was a Hollywood affectation. He had grown up dirt poor and hungry in Vienna (except for a few years when he was dirt poor and hungry in New York). His salvation was his proximity to Vienna’s Prater, the great amusement park, where he immersed himself in “pirouetting fleas, sword swallowers, tumbling midgets and men on stilts,” to abbreviate the long and fond list in his memoirs. The working inhabitants of “The Blue Angel,” bear and all, naturally leap to mind. But Sternberg created a realm of adamant illusion in all the six films he went on to make with Dietrich, until his love began to feel more like entrapment and to look more like revenge.

She became slimmer, blonder, sleeker, her cheekbones carved by shadow, a golden nimbus haloing her hair. The melancholic weariness of her opening scene in “Morocco” (1930), their first Hollywood film, betrays an overly close study of Garbo, but once she dons a tux, kisses a woman, and seduces Gary Cooper, all in the next scene, she’s nobody but Dietrich (unless she’s Sternberg). Nowhere this side of female impersonation has such evident pleasure been taken in the artifice of womanhood: playing an errant spy in their next film, “Dishonored,” set in the Vienna of the First World War, she refreshes her lipstick and straightens a stocking while awaiting a firing squad. Veils, lace, feathers, and furs make her almost as elaborate a construct as the teeming Chinese railroad station that was created for the opening of “Shanghai Express”—their best film together. Both “Morocco” and “Shanghai Express” were hits in Germany, and a Nazi ban on the spies and traitors of “Dishonored,” in January, 1932, was again without effect, since the Party was still a year from power. But, in a new turn, the film’s Berlin première was disrupted by a band of belligerents, whom an informant of Dietrich’s perhaps too casually dismissed as “rowdies.”

A month later, Riefenstahl experienced her second epiphany, in a stadium packed with cheering rowdies at a Hitler rally in Berlin. She seems to have been as inspired to become part of Hitler’s enterprise as she had been with Fanck and his mountain films, and the possibilities for advancement now were much greater. She had recently directed a film of her own, “The Blue Light,” which brought into the open the mysticism of the mountain genre: Riefenstahl played an otherworldly girl, spiritually tied to the beauty of a crystal-lined cave on a mountaintop, who dies when greedy villagers hack out the crystal. Riefenstahl had surely not intended the political intimations later discerned in the film. But, according to Harry Sokal, who left Germany in 1933, the negative reviews by several Berlin critics, some or all of whom were Jews, prompted an outpouring of anti-Semitism from the outraged director, who at about this time, with notable obtuseness, urged Sokal to read “Mein Kampf.”

Riefenstahl met Hitler shortly after the Berlin rally, when an admiring letter she sent brought a surprisingly quick response. She was soon appearing in the Goebbelses’ opera box, or dancing at a soirée at their home, charming everyone at the sort of social events that she was able to disavow until Goebbels’s diaries were discovered, in 1992. (June 12, 1933: “She is the only one of all the stars who understands us.”) There were widespread rumors of an affair with Hitler, evidently false. But Hitler believed so firmly in her artistry that he contracted her to film the Party rally in the summer of 1933. “Victory of Faith” was well received as propaganda, but it was a rush job, carried out with modest means. Riefenstahl assured him that she could do better. When he entrusted her with the much bigger rally to be held the following year, he demanded only that she render it “artistically meaningful.”

“Triumph of the Will” met the demands of the man who commissioned and financed it. Sixteen cameramen with sixteen assistants, nine aerial photographers, a sound crew, a lighting crew, drivers, guards: some hundred and seventy men reported to a director who had become the most important woman and the most important artist in the Reich. Plans for the six-day rally, which brought more than half a million people into the medieval city of Nuremberg, were made side by side with plans for the film. Albert Speer, the “chief decorator” of the event, was responsible for the visual drama: the obliterating seas of flags, the towering eagle behind the speakers’ platform, the “cathedral of light” made up of anti-aircraft searchlights beaming upward in Valhallan splendor. And all of it not only captured by Riefenstahl’s cameras but magnified and mythologized, so that the film itself has become a part of the history it documents.

It begins amid the clouds, from whence the Führer descends in his plane to spread joy among his people and to oversee a furiously rehearsed Nazi machine. Cranking up the sort of ingenuity she’d learned from Fanck, who mounted cameras on downhill skiers, Riefenstahl set her cameras gliding along tracks, soaring high in a specially built elevator, whizzing along with a crew on roller skates: every scene is in motion. Speeches by Party leaders were reduced to a few pithy lines (Julius Streicher: “A nation that does not protect its racial purity will perish!”) and reshot when necessary on a studio set. Hitler, in countless closeups, is viewed worshipfully from below, his face against the sky, his every word provoking an electric response. This is the leader, still consolidating power, whom the German people came to know. As much as any Hollywood director, Riefenstahl turned a human being into a god and urged a nation to fall hopelessly in love.

“O.K., you’ve pretty much nailed D minor.”

She completed one more major film before the start of the war, “Olympia,” a two-part record of the 1936 summer Olympics, in Berlin, which was used as a showcase for the ostensibly peaceful new regime. Even more ambitious as filmmaking, involving further innovations—powerful telephoto lenses, underwater cameras—“Olympia” was no more a straightforward record of events than “Triumph of the Will.” Practice sessions were spliced in, winners replicated their feats, film segments of the diving sequence were reversed to suggest the exhilaration of flight: this was a tribute to human strength, striving, and beauty. The surprisingly close attention that Riefenstahl’s cameras paid to Jesse Owens, the African-American star of the games, was meant to assuage the world’s fears about German policies, as were the many images of a smiling, chatting, unprecedentedly “human” Hitler. And yet Riefenstahl’s shots of Owens have an undeniable warmth. It’s an insoluble paradox that she demonstrates real devotion to the achievements of both men.

The enormous expenses of “Olympia” got Riefenstahl into funding fights with Goebbels, leading to the rumors in the Paris papers that only slightly marred her reception at the Exposition there in 1937. But “Olympia” was her greatest success yet. It had its première as the climax of Hitler’s birthday festivities, in April, 1938; Goebbels awarded her the German Film Prize. Intended for an international audience, the film was shown to prolonged applause through much of Europe before Riefenstahl set off for Hollywood to obtain American distribution. She reached New York in early November, just days before Kristallnacht, which she claimed was a slanderous falsehood perpetrated by the American press. Arriving in Hollywood some two weeks later, she found that no major figure except Walt Disney was willing to see her.

Dietrich was not in Hollywood at the time. Her last three films with Sternberg had been commercial disasters, as exotic fantasy gave way to hysterical extravaganza. She still believed she needed him as a director, but he had grown sick—to judge by the films, very sick—of being needed only in that way. There’s little love in the camera’s eye for anything but the Byzanto-crazy sets and costumes of “The Scarlet Empress” (Dietrich as Catherine the Great), and there’s a definite cruelty in its regard for her in their final film, “The Devil Is a Woman”: harshly made up—her semicircular eyebrows suggest permanent shock—and wearing a fringed lampshade on her head, she’s a parody of the woman she used to be. Paramount soon let her contract expire. During the late thirties, she travelled in Europe, failed to persuade her mother and sister to leave Germany, and made a few films that were less interesting than her list of lovers, which included Erich Maria Remarque and the French actor Jean Gabin. It was Gabin’s decision to join the Free French in North Africa that made Dietrich realize she could not “let the war pass me by.” At the end of 1943, she joined the U.S.O. and took on the greatest role of her life.

It’s hard to say whether her true uniform was the Eisenhower jacket, which she made appear the height of chic, or the sequinned gowns she wore onstage in front of the troops, singing and sometimes playing a musical saw—a ridiculous instrument that she used to tremendous effect, hoisting her skirt and placing it between her legs to sound a tune. She started out in Algiers and travelled the length of Italy, following the boys, often giving two shows a day in primitive conditions: Naples, Anzio, Rome, eventually Belgium, and finally into Germany. She put in more time at the front than any other performer. She sang on the radio, too, broadcasting not only to Allied troops but behind German military lines: her specialty was “Lili Marlene,” a soldier’s love song so sad that Goebbels banned it as demoralizing. (Dietrich’s friend Ernest Hemingway wrote that “if she had nothing more than her voice she could break your heart with it.”) Shortly after V-E Day, she travelled to the camp at Belsen, where she’d heard that her sister had been found, only to discover that she was not a prisoner but had been helping her husband run a movie theatre for Nazi personnel, living comfortably amid the horror. The Americans hushed up the story to spare their tireless warrior the headlines. Dietrich took care of her sister, quietly, for many years, but never spoke of her again.

People lie, and so do images. Early in the war, after witnessing a pogrom by German soldiers, Riefenstahl backed out of a film she’d begun making about Hitler’s victories at the Polish front. If her conscience troubled her further, though, she hid it well: the same month, she was on the dais at the victory celebration for the taking of Warsaw. She made no more official Nazi films, but the inverted mountain movie that she worked on during the war, titled “Lowlands,” was lavishly financed by the Reich. Starting in 1948, she was put on trial four times; in the end, she was judged to be nothing worse than a “fellow-traveller.” As for Dietrich, no one else would have been asked to play the Nazi-collaborating cabaret singer in “A Foreign Affair” (1948), a Hollywood film set in bombed-out Berlin. The Vienna-reared director, Billy Wilder—a Jew whose mother was murdered by the Nazis—confounded every expectation by favoring Dietrich’s morally ambiguous temptress over Jean Arthur’s shrilly all-American ingénue. Dietrich, glittering and gorgeous, sang her darkly cynical numbers (“Want to buy some illusions, slightly used?”) accompanied at the piano by the composer Friedrich Hollaender, who had written the songs for “The Blue Angel,” eighteen years earlier, shortly before he, too, fled to Hollywood. In these two films, Dietrich embodies the bold beginning and the tragic end of the same German story.

Dietrich’s real-life heroism allowed her to play women who had shown none of her moral courage and invest them with human dimension. In 1948, when the publication of the fraudulent diaries of Eva Braun “revealed” salacious stories about Riefenstahl, newspapers gleefully predicted “Marlene to play Leni” in the movie version. She might have lent even this role some sympathy. She is said to have based the exquisitely cultured and willfully unknowing Nazi she played in “Judgment at Nuremberg,” in 1961, on her mother.

Riefenstahl’s redemption, beyond the military courts, was a subject of fierce argument for the rest of her very long life—she died in 2003, a decade after Dietrich, at the age of a hundred and one. She never saw the need to offer an apology, and her memoirs, which appeared in Germany in 1987, were filled with self-justifying fabrications. But the fact that the two major films Riefenstahl made for the Nazis remain so powerful has meant that the real argument is about art. We do not expect artists to be heroes, but we have come to accept that the art of totalitarian regimes is, by a kind of moral corollary, bound to be bathetic kitsch. It is deeply unsteadying to ponder the possibility that Riefenstahl might have been both a considerable artist and a considerable Nazi. Critics have long pressed for resolution, one way or the other.

As early as 1955, a group of American film directors—many of whom had refused to see Riefenstahl when she came to Hollywood in 1938—named “Olympia” one of the ten best films ever made, alongside “Battleship Potemkin” and “Citizen Kane.” Just a decade after the war, one could presumably tell the artist from the art. In 1965, Susan Sontag wrote that both “Olympia” and “Triumph of the Will” transcended “the categories of propaganda or even reportage,” but she changed her mind when, nine years later, her position no longer seemed a daring stand for formal values but a dangerous commonplace, with the two films becoming festival favorites and the director approaching the status of a pop star.

In 1973, Riefenstahl launched a new career as a photographer, with a lauded book of color images of the Nuba, a majestic tribe in remote central Sudan. The subject, as far from her past as possible, supported the increasingly widespread contention that the only constant in her work was a devotion to physical beauty, without regard to race. Sontag, in an essay that seems to have made Riefenstahl angrier than anything Hitler had done, countered that the only constant in Riefenstahl’s work was its inherent Fascism, evident precisely in this devotion to physical beauty, among other things, and in its exclusion of human complexity. It’s a strong argument about intention: a refusal to separate the artist from the art. The photographs, however, remain indistinguishable in any moral or political sense from those taken of the Nuba by George Rodger, the English war photographer whose work inspired Riefenstahl, and whose perspective was anything but Fascist: Rodger, accompanying the British Army in 1945, had been among the first to photograph the corpses at Belsen.

The dedication to beauty had its dangers for Dietrich, too. She spent much of the last two decades of her professional life on the concert stage and on the move, from Paris to Las Vegas, stirring memories and breaking hearts—she sang “Lili Marlene” again in Germany, and in Israel—and punishing her body beyond endurance to maintain the glamour of years past. From the late seventies, when the glamour seemed beyond recall, she sequestered herself in her Paris apartment. Her “Judgment at Nuremberg” co-star, Maximilian Schell, made a documentary film about her when she was eighty-one, without being allowed to photograph her. Billy Wilder promised that he’d blindfold himself if only she’d let him visit her, but she declined.

One might have expected Riefenstahl to be the isolated one, but freedom from shame proved a great advantage. She shared her later years with a devoted camera assistant four decades her junior. She took up scuba diving in her seventies, and continued straight through her nineties, posing in her bathing gear and publishing books of underwater photographs, practically daring anyone to talk about Fascist images of fish. Yet the old questions continued to vex her. “So what am I guilty of?” she asked an interviewer in the final moments of a three-hour documentary about her life, released in 1993. “I didn’t drop any atomic bombs. I didn’t denounce anyone. So where does my guilt lie?”

Near the end of “Judgment at Nuremberg,” Dietrich, the widow of a convicted Nazi general, waits expectantly for the verdict in the American military trial of four German judges. Like her husband, these men were not blatant monsters but influential figures who went along with the monstrous plans. The movie, directed by Stanley Kramer, is a document of its time: the late fifties, when people were just beginning to come to terms with the Holocaust. One of the trial scenes contained actual footage from the liberation of the camps, the first such images that many people had seen. Dietrich’s role—written with her in mind—is the aggrieved persona of German innocence. “Do you think we knew of those things?” she asks the American judge, offended in her dignity. “We did not know. We did not know.” The verdict, nevertheless, is guilty. In the aftermath, the judge calls her to say goodbye, and Dietrich has one of her finest moments, with no lines to say at all: there is just her magnificent face, half in shadow, suddenly aged and blanched of life, as she sits silently and lets the telephone ring.