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Parallel Worlds Science Fiction

Parallel Worlds Science Fiction are stories about traveling to parallel worlds or universes. The parallel world can be vastly different from our own, or very recognizable. While Parallel Worlds and Alternate History stories frequently overlap, generally, Parallel Worlds differ from Alternate History because a parallel world exists alongside our own. There are also some tie ins to Time Travel subgenre as well, with the parallel world conceit used to explain the grandfather conundrum (if you go back into the past and kill your grandfather, why you might still exist, the answer being that such an action kills your grandfather in a parallel world while you exist in a world your grandfather didn't die).

There are an infinite number of parallel universes--at least theoretically. This idea is based on probability, think about flipping a coin. For example, in the animated series Futurama, the episode "The Farnsworth Parabox" the Planet Express team enters a parallel world where the key difference is that coin flips have opposite outcomes. The concept can be extrapolated out infinitely, every time something happens, something else could have happened and did happen, just in a parallel world.

You can view the crowd-ranked "Popular" Parallel Science FIction Book list and vote and/submit entries to it.


  • Level of Real Science

    Low. While some scientists may reasonably postulate the existence of parallel worlds within a grand multiverse, they do not believe that travel between them is possible. With little real-world science applicable to the existence and travel between parallel worlds, this sub-genre has weak scientific explanations, like wormholes and hyperspace.

  • Level of Grand Ideas/Social Implications

    High. Unless the story is a comedy or a pulp, chances are the level of grand ideas is high. Parallel Worlds stories have been used for social commentary and historical speculation since its inception.

  • Level of Characterization

    Moderate. Characterization is a large component of world-building for Parallel Worlds Sci Fi. Characters are how readers are transported and connected to these fictional parallel worlds so characters have to be three dimensional otherwise readers will not be invested and will not be able to follow the story. That being said, a Parallel Worlds/Pulp Sci Fi crossover is not likely to have original characters.

  • Level of Plot Complexity

    Moderate. In its more simplistic understanding, Parallel Worlds Sci Fi has two types of plots: someone from our world is transplanted to another world and goes on adventures, or a communication or visitor from another world has some kind of impact on our world.

  • Level of Violence

    ariable. There is lots of freedom for writers of the Parallel Worlds sub-genre--it is truly a genre of anything can happen. As such, violence can be graphic or nonexistent.

Related Science Fiction subgenres

  • Alternate History. Frequently, a parallel world is much like our own, but its timeline is really an alternate history. Also see our Best Alternate History list

  • Time Travel. If time travel is possible, so too should travel to parallel worlds. Both of these sub-genres have similar tropes like wormholes to explain how characters are able to traverse time and space. Pulp Science Fiction. The pulp writers grabbed hold of the parallel worlds concept and used it for many sensational stories.

Popular Parallel Worlds Science Fiction Books