This was a banner year for science fiction and fantasy books — and choosing the year's best titles was harder than usual. From time-slashing serial killers to grand space operas to Kafka-esque nightmares, this was a year of brilliant reads. Here are the 20 best science fiction and fantasy books of 2013.

Neptune's Brood by Charles Stross

The perfect book for the strange economic daymare we've all been trapped in for the past five years — with Neptune's Brood, Stross turns his searing curiosity onto the murky realm of bankers.

A stand-alone follow-up to his Saturn's Children, this novel sees a posthuman historian of accountancy practices, Krina Alizond-114, searching for her missing cousin while trying to figure out why so many people want her dead. But the real thrills in this novel come from Stross' wily speculations about interstellar economics — you can see why this was Paul Krugman's favorite book ever.

Abbadon's Gate by James SA Corey

Daniel Abraham and Ty Franck continue to deliver the awesomeness in their third volume in the Expanse series of space opera novels, written as James S.A. Corey.

This time around, James Holden and his crew are investigating the alien artifact discovered out beyond Neptune's orbit — only to discover they're the target of a new conspiracy. With each installment, you wonder how Abraham and Franck will manage to top themselves — and they keep doing it.

The Shining Girls by Lauren Beukes

The acclaimed author of Moxyland and Zoo City channels Jonathan Demme's Silence of the Lambs in this story of a serial killer who finds a house in 1931 that lets him travel through the decades, up to 1993, killing girls who have the potential to change the world. Until one girl escapes, and dedicates her life to stopping him.

The Ocean at the End of the Lane by Neil Gaiman

Gaiman's first novel for adults in years is a slimmer volume than his American Gods, but it still brings immense depth.

This story of a man returning home for a funeral and delving into the murky waters of childhood memories shows how your own past can be the strangest realm of all, as Gaiman juxtaposes routine childhood fears with traditional fantasy scares.

NOS4A2 by Joe Hill

Hill channels the classic novels of his dad, Stephen King, with this story about another one of those serial killers who travels through uncanny realms and preys on special children. The one child who got away from Charles Talent Max, a girl named Vic, grows up to find that Manx has taken her son — and the creepiness just starts there.

Republic of Thieves by Scott Lynch

Lynch's long-awaited new novel about that charming bastard, Locke Lamora, doesn't disappoint in the slightest — everything you loved about that rogue is back in full force, even as Lamora is in worse straits than ever before.

Poisoned and in dire straits, Lamora needs all his cunning to survive — and meanwhile, we finally meet the mysterious woman from his past, Sabetha, who fully lives up to our anticipation.

Love Minus Eighty by Will McIntosh

Based on his Hugo-winning short story "Bridesicles," McIntosh's newest novel turns an ultra-creepy premise (rich men defrost cryogenically frozen dead girls for "dates" or marriage) into a surprisingly charming cross between Philip K. Dick and Jane Austen.

From the lesbian who finds herself accidentally frozen in a heterosexual dating center to the dating coach who helps the woman who's stealing the man she loves, McIntosh shows how love is never easy — even if technology lets you revive the dead and live virtually forever.

Aliens: Recent Encounters, edited by Alex Dally MacFarland

There were a lot of anthologies this year, including several with ambitious themes — but this one blew us away more than any other.

Mostly because of the sheer volume of greatness contained in these 32 stories, ranging from Ken Liu's "Bookmaking Habits of Select Species" to Ursula K. Le Guin's "Seasons of the Ansarac." These are classic stories of alien encounters, from some of the best science fiction writers working today.

The Accursed by Joyce Carol Oates

At last, Oates completes a novel she left unfinished for years — a capstone to her string of gothic novels. And this one's a doozy.

A historical fantasy that includes real-life figures like Mark Twain and Woodrow Wilson, The Accursed is a taut supernatural mystery about an ageless figure who abducts a young woman on the brink of getting married, and the man who tries to get her back. A sly, subversive look at repression and class divisions at the turn of the 20th century.

The Violent Century by Lavie Tidhar

Another historical novel, but this one's an alternate history featuring superheroes in a somewhat different version of World War II and the Cold War.

Tidhar made a splash with his daring, off-kilter novel Osama, but this time around he's delving into the horrors of the twentieth century with a story of intrigue that blends spy drama with superheroic thrills — and even if you think you've seen everything in the superheroic realm, Tidhar will prove you wrong.

The Golem and the Jinni by Helen Wecker

Here's another fantastical novel that takes place at the turn of the 20th century — but this time featuring a meeting of supernatural beings from Jewish and Arab mythology.

A golem named Chava survives the death at sea of the rabbi who created her and arrives in New York in 1899, where she meets Ahmad, a jinni who was born in ancient Syria — and the two of them form an unlikely bond. This book appears to be a simple fairy tale at first, but it raises serious philosophical questions and explores the clash of cultures in the New World.

We Are All Completely Beside Ourselves by Karen Joy Fowler

Like Gaiman's Ocean, this is another book about probing buried memories, and dealing with the mysterious, tricky space of childhood.

But the protagonist of Fowler's novel has a very different sort of childhood to explore, one in which she was part of a strange science experiment that has left strange traces in her life. Even as Fowler keeps reminding us how unreliable our memories are, she builds a jarring image of Rosemary's bizarre experiences.

You by Austin Grossman

The author of Soon I Will Be Invincible is back with a novel that trades on his own experiences working in the video-game industry.

This time around, Grossman explores more profound territory, delving into how video games rewrite our real-life experiences, and how gameplay has a way of changing your very identity. A great read for anybody who's fascinated by the mechanics of storytelling, and how fantasy shapes our perceptions of reality.

Hild by Nicola Griffith

The author of Ammonite and Slow River returns to the realms of the fantastical — sort of — with this spellbinding historical novel about the 7th century woman who will become St. Hilda of Whitby.

Nicola's effortlessly immersive descriptions of life in the Middle Ages will enthrall you, but so will her depiction of a woman trying to survive as the Seer in a society that believes in prophecy and conflicting gods. A must-read for anybody who writes (or reads) historical fantasy.

Something More Than Night by Ian Tregillis

A noir pulp detective novel set in the classical vision of Heaven, featuring angels, cherubim and the Voice of God — it could have been a genre pastiche, more concerned with being amusingly self-referential than actually engaging.

Instead, it's a masterwork with more layers than you realize at first. Tregillis uses his genre tropes as a way to show how we reconstruct reality according to the stories in our heads — and you see how this could be a problem when you're dealing with immortal beings and cosmic mysteries. Still not sure how I feel about the final twist in this book, but I love it overall.

Life After Life by Kate Atkinson

This novel took the book world by storm earlier this year, and it's easy to see why — it's like The Time Traveler's Wife, except with a healthy dose of Downton Abbey. But it's even better than that makes it sound.

Ursula Todd dies as a baby in 1910 — but then her life restarts, and this time she lives. She dies again, and again, but each time her life is rewritten so that she lives, and we see different alternate paths that her life could have taken. The result is a fascinating look at tragedies that might have been, and the way that history always sweeps us forward.

The Best of All Possible Worlds by Karen Lord

Even in a year of weird books, this is an odd one — it starts with a massive genocide, with the homeworld of the Sadiri being wiped out in a brutal attack. And then it turns into a light romantic comedy, as the last surviving men of the Sadiri race try to find brides to mate with.

Yes, it's Seven Brides for Seven Post-Apocalyptic Brothers. But at the same time, Lord takes you through the Sadiri diaspora on another planet, and we see how the Sadiri culture has changed as a result of being scattered.

Tenth of December by George Saunders

These days, everybody is channeling Franz Kafka, and we've lost count of the jarring short stories about bewildering transformations and confounding officialdom that we've read. But with this book, George Saunders shows us what being dwarfed by an unforgiving world is really all about.

As usual, Saunders' protagonists are trapped in a world they can't control, and with these stories he gets further into the heart of our complicity with evil, and our capacity for self-deception. The real surprise here is how much compassion Saunders has for his ruinous characters.

MaddAdam by Margaret Atwood

The trilogy that began with Oryx and Crake concludes, and the series ends in a startling, fascinating way that confirms this as a major work.

This time around, she finishes tearing down the world that Big Science made — and gives us a surprising glimpse of hope. The trilogy emerges as a techno-realist story of humanity's self-destruction, but also our redemption.

Ancillary Justice by Ann Leckie

This list isn't strictly a countdown — but Ancillary Justice is definitely our #1 pick of the year's best science fiction or fantasy book.

If only for the intense, excited conversations we've had about its portrayal of a spaceship consciousness and interstellar politics. This Iain M. Banks-esque tale was the book that made us most excited about the future of science fiction in 2013.

Additional reporting by Annalee Newitz, Andrew Liptak and Michael Ann Dobbs.