Satan from the 7th grade
 Adam Cisowski, a precocious and "devilishly clever" high school pupil (the "satan" of the title) spends a summer holiday at a run-down country house, presided over by "The Professor" - an aristocratic, eccentric mathematician who is friendly and affable but completely improvident. Suddenly, treasure hunting is launched by the discovery that an officer of Napoleon's Grand Army, who was taken care of by the Professor's ancestors in the aftermath of the disastrous 1812 invasion of Russia, may have left to his benefactors a hidden treasure (which would be very great help for their impoverished present-day descendants). However, the subtle trail of hints left by the French officer defy all minds but that of the "devilish" Adam. Adam energetically takes up the challenge, seeking to help his hosts - and in particular, win the heart of Wanda, the Professor's beautiful daughter. Throughout the book, he follows the perplexing trail, clue after clue, using hints from such sources as Dante's Inferno. Adam must, moreover, play a dangerous game of cat-and-mouse with a nasty gang of criminals, who also got the scent and who are very determined to lay their own hands on the treasure. At a certain moment the search looks like having gotten to a dead end - a vital hint had been written on the door of an outbuilding, but the door is not there any more. It turns out, however, that the door in question was used as an improvised stretcher on which a wounded rebel was carried to a neighbouring village during the Polish 1863 uprising against Russian rule - and that after this use, the door had been installed at the village church, where Adam duly finds it and writes down the clue. Finally, Adam finds the treasure - not before providing the criminals which he knows to be following him with a red herring and letting them "rob" from him a heavy old cask full of worthless scrap iron. They open the cask with much trouble, suspect each other of cheating, get into a violent quarrel, and get arrested by the police. The true treasure, meanwhile found hidden in a stork's nest, is more lightweight - a small sack full of jewellery which the French officer presumably looted in Russia, and whose worth is more than enough to provide for the Professor and his family. In the book's final sentence, Adam looks from the glittering jewels to Wanda's eyes, and finds them "more precious than all treasures in the world". Israeli reviewer Aryeh Klein noted that in retrospect, the book assumes an unintended wilfulness: "The present-day reader knows, as the writer could not, that this is 1937 and that the horrors of Nazi occupation are just two years ahead for all these sympathetic characters in their pastoral countryside. In order to survive, Adam would all too soon need to outwit enemies far more brutal and ruthless than the book's rather clumsy gang of criminals". fr:Satan de la septième classe pl:Szatan z siódmej klasy