With “Everything Everywhere All At Once” sweeping up award nods all across this Earth and (we assume) some parallel realities besides, the multiverse is firmly back in the spotlight. The idea that the universe we know is just one in an infinity of worlds has captivated writers for generations. So what’s old, what’s new, and what lies just beyond the thin membrane of reality? Join us as we try to make sense of it all, through books.

Silvia: A few years ago, someone asked me if I could predict an emerging trend in speculative fiction, and I said more multiverses. Most literary predictions don’t come true, but I think I was on the right track. Books like Matt Haig’s “The Midnight Library” (2020), about a woman who is able to see the alternate existences she might have lived, or Micaiah Johnson’s “The Space Between Worlds” (2020), where a multiverse traveler must find out who murdered her counterpart in another reality, have struck a chord with many readers.

But who invented the concept of the multiverse? One popular answer is Michael Moorcock, who imagined a series of parallel realities inhabited by the Eternal Champion, a figure who maintains the balance between order and chaos. One of these champions is Elric, a tormented albino prince with a magical sword that feeds on the souls of the ones killed by it. The Elric stories have been collected in several volumes, including last year’s “The Citadel of Forgotten Myths.” Because it is technically a prequel, “Citadel” offers a good entry point to the saga. This summer, Titan Comics will release “The Michael Moorcock Library: Multiverse, Vol. 1,” which collects comic books from the 1990s.

Elric’s stories originally appeared in the 1960s, but I read them as a teen in the early ’90s, and they were my first foray into multiverses, along with the TV show “Sliders.” What was the first book with the concept of a multiverse that you read?

Lavie: The multiverse is a very current theme – Alix E. Harrow’s “The Ten Thousand Doors of January” (2019) is a charming take on the topic, as is Susanna Clarke’s “Piranesi” (2020), which draws for inspiration on C.S. Lewis’s “The Magician’s Nephew” (1955) with its “Wood Between the Worlds” that connects multiple realities. But I’m going to go old-school and reference a couple of short stories. Isaac Asimov’s “Living Space” (1956) has an infinity of empty Earths, so that every person gets an entire planet to themselves. At least until some unsavory characters move in next door. And in Clifford Simak’s “The Big Front Yard” (1958), an intergalactic stargate opens up one day in a man’s home. Simak revisited the theme in his classic novel “Way Station” (1963), about the human keeper of one such portal.

The big one, though, is undoubtedly Roger Zelazny’s classic “The Chronicles of Amber,” beginning with “Nine Princes in Amber” (1970), which starts, in classic hard-boiled style, with Prince Corwin of Amber waking up on our Earth (following an “accident”) without his memory. It doesn’t take him long to figure out that he is heir to the throne of Amber, the one true world of which all other worlds are “shadows” – and that he has the ability to move between them. Zelazny was inspired by Philip José Farmer’s “World of Tiers” sequence, beginning with “The Maker of Universes” (1965), in which an immortal who also lost his memory on our Earth discovers he is the lost ruler of a pocket universe and has the ability to move between worlds.

Charles Stross’s “Merchant Princes” series, beginning with 2004’s “The Family Trade,” is an homage to Amber, where merchants exploit the commercial possibilities of the multiverse. George R.R. Martin, a close friend of Zelazny, was himself inspired by the Amber novels for his “A Song of Ice and Fire” sequence, beginning with “A Game of Thrones” (1996), which eschews the multiverse but keeps the murderous machinations of royalty for the throne. (Martin has been behind several attempts to bring Zelazny’s work to screen, and the “Amber” books have recently been picked up again, this time by Stephen Colbert.)

Silvia: I loved the “Amber” books when I was younger. I also read the “Morgaine Cycle” by C.J. Cherryh, beginning with “Gate of Ivrel” (1976), in which a mysterious woman travels between worlds on a mission to close the gates connecting them. This is one of those novels where any sufficiently advanced technology is indistinguishable from magic, so even if it feels like sword and sorcery, there’s a scientific explanation.

Finally, Philip Pullman’s young-adult series “His Dark Materials,” which began with “Northern Lights (The Golden Compass)” in 1995, takes place in a multiverse across several worlds, and concerns, among other things, a quest to find the nature of a mysterious element called “Dust.” Are there any other multiverses you remember fondly?

Lavie: I have a soft spot for the original “Gunslinger” stories by Stephen King, which became the “Dark Tower” sequence. But pick up any of these, and I don’t think you could go wrong! What about you, dear reader: Which multiverse book is your favorite?

Silvia Moreno-Garcia is the author of “The Daughter of Doctor Moreau” and “Mexican Gothic.” Her newest novel, “Silver Nitrate,” will be published in July. Lavie Tidhar’s latest novels are “Maror” and “Neom.”