 Sandra Miesel wrote a new prologue that was added to the series' republication in the 1980s and formally transformed it from future history into alternate history.Her prologue took the divergence point from our own history as the (premature) death of U.S. President Dwight D. Eisenhower in 1956 (in our world he died in 1969), and the assumption of power by a younger, hotheaded Richard Nixon, which led to exacerbation of the Cold War and a devastating nuclear war in 1958.In the war's aftermath, a science called psychodynamics is created.