The End of Eternity

The End of Eternity is a 1955 science fiction novel by the American writer Isaac Asimov. It mixes time travel and social engineering with the machinery of a mystery and was shortlisted for the Hugo Award for Best Novel.

The book's premise is a closed society of specialists called Eternals who occupy a section of time running alongside ordinary history and travel up and down it making small corrections. Their purpose is to reduce human suffering, and the accumulated effect of centuries of tidying is a stable world in which certain kinds of ambition, space travel among them, have been edited out of reach. Andrew Harlan is a Technician who carries out those adjustments, and his work and his private life come into conflict with the rules that Eternity exists to protect.

Asimov built the plot around a causal loop, a paradox in which events and their causes form a circle. It is one of the books in which he worked out ideas he later returned to in his Foundation and robot stories.