阿西莫夫|The End of Eternity 永恒的终结

Science-fiction godfather Isaac Asimov published his classic time-travel novel The End of Eternity in 1955, and in a way, it's become lost in time itself over the years. Overshadowed by Asimov's famous Foundation and Robot series, The End of Eternity is mostly unknown to casual science-fiction fans. Yet serious devotees of Asimov's work consider it to be his single greatest novel.

The End of Eternity has been out of print and hard to find for a while, but that's been happily remedied with Tor Books' recent hardcover reissue and even more recent move to the various e-book formats.

The complicated plot of the book goes something like this: Our hero, Andrew Harlan, is an Eternal — a scientist operating from a tract of cosmic real estate known as Eternity. Eternity is a sort of bubble that exists outside of time and space. Or, in the metaphorical approach of the book, it's like an extratemporal elevator shaft running parallel to forward-moving Time.

Eternals can move up and down this shaft — "upwhen" and "downwhen" — getting off at stations in any century to enact Reality Changes. These changes alter the flow of human events toward outcomes producing "the maximum good for the maximum number."