The End of Eternity by Isaac Asimov is a science fiction novel, with mystery and thriller elements, on the subjects of time travel and social engineering.
The themes are very different from most of his robot and 'space opera' stories, and take a clever approach to time paradoxes. Some people consider it his best work, or at least one of the best. (This view is recorded in the Encyclopedia of Science Fiction.)
In December 1953, Asimov was thumbing through a copy of the March 28, 1932 issue of Time when he noticed what looked at first glance like a drawing of the mushroom cloud of a nuclear explosion. A longer look showed him that the drawing was actually the Old Faithful geyser. However, he began pondering the question of what the implications would be if there had been a drawing of a mushroom cloud in a magazine from 1932, and he eventually came up with the plot of a time travel story. He began the story, called "The End of Eternity" on December 7, and finished it on February 6,...
full article at wikipedia
