It seems like there’s been an uptick in parallel world tales of late. Perhaps outer space holds less appeal as a new frontier for science fiction; alternate earths, instead, are where the greener fields lie—sometimes literally. Neal Stephenson has produced his own riff on the many-worlds theory in Anathem, and Iain M. Banks’s Transition features a secret organization of “transitionaries,” who slip from one world to the next by temporarily taking over the bodies of inhabitants of each world. Matt Fraction’s comic Casanova is about an assassin yanked out of his own timeline to replace his own alternate self in another as part of a complex, worlds-spanning espionage scheme. Even Doctor Who has played extensively with parallel worlds and alternate timelines. The latest addition to the genre: The Long Earth, a collaboration between Terry Pratchett and Stephen Baxter.
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