It was pointed out to me that I overlooked an obvious alternative to implausible faster-than-light travel in this essay: there’s no need to travel long distances to visit extrasolar worlds if one can simply step from one version of Earth to another version.
Flash of Two Worlds, The Flash, vol. 1, #123 by Gardner Fox (1961)
When a magician fails to appear at Iris West’s charity event, the Flash—the world’s fastest man—steps in to entertain the children with super-speed stunts. One stunt has an unexpected effect: the Flash finds himself in the world of the childhood comics that inspired him, a world where Jay Garrick and not Barry Allen is the Flash.
Inadvertently inventing interdimensional travel is remarkable enough. But something else noteworthy has happened: three master supervillains have come out of retirement in the alternate Earth. At forty-plus, Jay Garrick may be too old to stop all three himself. Clearly, the Flashes of two worlds must team up, in what will be the first of many cooperative ventures between the worlds in the decades to come.
Shadow of Earth by Phyllis Eisenstein (1979)
Spanish tutor Celia Ward has fallen hard for her student Larry Meyers. When she discovers that the older man has an alarming stash of firearms, she does not immediately flee. Instead, she lets Larry spin an enthralling tale about his project to explore alternate Earth, a project for which the arsenal is a necessary element. The story is true. More importantly, confiding in Celia buys the reprehensible Larry enough time to come up with a plan to silence Celia before she blabs to the authorities—a plan that is not only effective, but highly profitable.
In a North America one accident of fate away, the Marquis de los Rubios believes himself to be of an elevated breed. Such a man demands a bride of rare qualities. Such women are difficult to find in the Marquis’ feudal New World. Newly arrived Celia is just the kind of woman he wants. However Celia has no interest in becoming a racist lord’s brood mare. However, the universe into which Larry has enticed her is not one where women’s preferences matter. If Celia cannot somehow escape the Marquis and find her way back home, she faces a life of reproductive slavery.
Wildside by Steven Gould (1996)
In an America of the past, young Charlie Newell’s friends have dreams but no reasonable way to finance them, not even the usurious loans to which their modern-day counter-parts would turn. Charlie believes the land he inherited from his uncle could solve his friends’ problem. Along with a cabin and a rudimentary landing strip, Charlie’s little piece of heaven has a portal to a North America total bereft of humans.
A world without humans is a world filled with biodiversity long vanished from our world. It only remains for the teens to work out just how to turn that biological wealth into cold hard cash, and how to do so without attracting undue attention from an American government all too likely to appropriate the new world for its own use. Charlie and his friends succeed at the first. The second? Not so much.
The Space Between Worlds by Micaiah Johnson (2020)
The world may be on fire but Wiley City prevails, thanks to Adam Bosch’s marvelous invention, a portal to other universes. Wiley City now has access to 380 other universes, any one of which may have goods Wiley City desperately needs, necessities that sufficiently cunning agents may pilfer.
But, as always, there are catches. First of all, Bosch’s device can only reach worlds similar to his, which is to say versions of Wiley City in equally dire straits. Second, two copies of the same person cannot be in the same world and live. Cara is financially desperate enough to accept the risks hiring on as an agent and venturing into other worlds. Poverty in all Wiley City worlds has caused 372 of her analogs to die young. No other agent can visit as many worlds. Steady employment is guaranteed—at least until her boss can work out how to rid himself of the embarrassing necessity of relying on peons like Cara.
The Art of Saving the World by Corinne Duyvis (2020)
Hazel Stanczak cannot visit other Earths. In fact, she cannot even leave the farm where she was born. If she does, the rift that appeared on the farm when she was born will go wild. The Mysterious Government Agency (MGA), too top secret to share its name with the family whose lives they manage, insists Hazel stay put.
On Hazel’s sixteenth birthday, an unknown threshold is passed. The gate ejects alternate versions of Hazel into her world. It decouples from the farm, spewing ravenous trolls as it drifts across America. The entities responsible for the interdimensional gate intended that Hazel step into the role of chosen one, or as the beings might put it, the star of a delightful apocalyptic reality show in which thousands of humans will die, quite likely including Hazel herself. Hazel being unwilling, they plan to ensure she has no choice in the matter.
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There are, of course, lots and lots and lots and lots of stories involving access to parallel worlds. These are just five so the odds that I didn’t mention your favourites are pretty high. Comments are, as ever, below.
In the words of fanfiction author Musty181, prolific book reviewer and perennial Darwin Award nominee James Davis Nicoll “looks like a default mii with glasses.” His work has appeared in Publishers Weekly and Romantic Times as well as on his own websites, James Nicoll Reviews (where he is assisted by editor Karen Lofstrom and web person Adrienne L. Travis) and the 2021 and 2022 Aurora Award finalist Young People Read Old SFF (where he is assisted by web person Adrienne L. Travis). He is a four-time finalist for the Best Fan Writer Hugo Award, and is surprisingly flammable.
