In 1982 Fritz Leiber explained the unique idea that drives his Hugo Award–winning 1958 novel The Big Time:
To dramatize the effects of time travel, science fiction usually assumes that if you could go back and change one crucial event, the entire future would be drastically altered. . . . But that wouldn’t have suited my purposes, so I assumed a Law of the Conservation of Reality, meaning that the past would resist change (temporal reluctance) and tend to work back quickly into its old course, and you’d have to go back and make many little changes, sometimes over and over again, before you could get a really big change going—perhaps the equivalent of an atomic chain reaction.In the novel, the would-be masters of the future universe abduct the soldiers for their wars from various armies in the past. As Neil Gaiman summarizes the novel’s plot in a new appreciation, “There are two sides in the Change War, Spiders and Snakes: they both enlist the recently dead in their armies, pluck them from time moments before they die and have them battle to ensure that something, somehow, somewhen, comes out the way it should to (we assume) guarantee one side or the other ultimate victory.”
Leiber recalled, “The energy I generated writing this novel of the Change War of the Spiders and Snakes (as I called the two sides, to keep them mysterious and unpleasant, as major powers always are, inscrutable and nasty) overflowed at once.” He incorporated his surplus ideas into a number of stories set in the same universe—including this week’s Story of the Week selection, “Try and Change the Past.”
Readers should be sure to check out The Library of America’s new American Science Fiction online companion. The Fritz Leiber section features (in addition to Gaiman’s essay): a slideshow, a biography of Leiber, other Change War stories, audio for three 1950s adaptations of Leiber's stories from the NBC radio program X Minus One, and the foreword to a collection of Change War stories that concludes, “I sometimes think the powers that created the universe were chiefly interested in maximizing its mystery. That’s why I write science fiction.”
No, I wouldn’t advise anyone to try to change the past, at least not his personal past, although changing the general past is my business, my fighting business. You see, I’m a Snake in the Change War. . . . If you don't see the full story below, click here (PDF) or click here (Google Docs) to read it—free!
You can also read this week’s story at the LOA online companion.