The End of Eternity is a science-fiction novel by Isaac Asimov. It was first published by Doubleday in 1955.
There is a group of people (only males) who are called The Eternals. They live outside time and their mission is to change the reality of humanity in order to make it a better reality. They try to do this with the help of computers and they then make the changes. They prefer minimal changes. They prefer to make "The Minimum Necessary Change".
Harlan, an Eternal, does the dirty work for this group, he is a Technician. There are several jobs on the hierarchy. He soon falls in love with a woman called Noys Lambent.
She believes, apparently, that by being in a relationship with him she can became Eternal too. Harlan's immediate superior Senior Computer Twisell, tells him the truth about his role in the creation of Eternity. Harlan must teach Cooper, who is really Mallansohn, the inventor of time field technology. Cooper completes the time circle created. Nevertheless, Harlan and Noys destroy the Eternity, honouring the title of the novel.
This novel is the second version of a previous novel with the same name. The original writing was shorter. Asimov came up with the idea for this story by reading an old Time magazine. He thought he had seen a toadstool, very similar to the atomic bomb. The problem was that the magazine was fifteen years before Hiroshima, according to Asimov's recalling of the anecdote. He thought of a way for a time traveller to send a message to the future in case he were trapped in the past. Then, Asimov started to write and came with a 25.000-word story in 1954. It was a great success as its longer version.