"Alternate history" is one of those sub-genres that tends to fly a bit under the radar. It gets lumped in with run of the mill historical fiction, or it gets shelved in the sci-fi section alongside robots and aliens. Unlike most science fiction, however, alternate history books don't look to the future. They look to the past. They zero in on one notable moment in human history, one war or plague or human rights violation, and ask "What if things had gone just a bit differently?" So if you find yourself wishing that you could change the past, pick up one of these excellent alternate history books for a scary—or enticing—take on what could have been.

After all, it does feel a bit like 2018 is an alternate timeline — like something went horribly wrong somewhere before 2016, and we've ended up in a poorly written HBO re-imagining of the early 21st Century. It seems like this year is definitely in one of the scarier "What if?" scenarios. But these books run the gamut from disturbing rewrites to utopian visions of the not-so-distant past. There are totally realistic historical twists and utterly fantastical takes on real life events. Check out some of the wildest, most chilling, and most enviable alternate histories that the book world has to offer:

'The Man in the High Castle' by Philip K. Dick Amazon This might just be the best known alternate history novel of all time, based on one of the most popular alternate history premises of all time: what if the Germans had won the war? Philip K. Dick introduces us to an America occupied by Nazis, where slavery is legal and all surviving Jews are now in hiding. It's definitively on the "disturbing" end of the alternate history spectrum, but worth reading for its unfortunate parallels to our not-so-alternate reality. Click here to buy.

'Naughts & Crosses' by Malorie Blackman Amazon Naughts and Crosses is less of a horrifying vision of the world, and more of a role reversal: What if Africans had historically enslaved Europeans, and not the other way around? This is the case for Sephy, a high status Cross, and Callum, a second-class naught, in a segregated society where any kind of relationship between the two of them is strictly forbidden (but since when has that ever stopped two kids in love?). Click here to buy.

'Farthing' by Jo Walton Amazon Churchill has been overthrown, and a group of Englishmen have negotiated "peace" with Adolf Hitler. Lucy's parents were leading members of this group of revolutionaries, and they're none too pleased that Lucy went and married a Jewish man anyway. Their disapproval becomes deadly, however, when Lucy's husband is framed for murder, leaving Lucy with one risky option to save him and herself... Click here to buy.

'Everfair' by Nisi Shawl Amazon Belgium is colonizing the Congo, led by the bloodthirsty King Leopold II. Only this time, the Congo has steam power on their side. Everfair re-imagines the "Belgian" Congo with a technological edge. In this version of history, a few bold revolutionaries are able to scrape together enough land to create the safe haven of Everfair, where African natives and escaped slaves can build the steampunk utopia of their dreams. Click here to buy.

'The Years of Rice and Salt' by Kim Stanley Robinson Amazon What if the plague, but much, much worse? In The Years of Rice and Salt, the Black Death has killed 99% of Europe's population (you'll notice that a lot of alternate history wish fulfillment involves wiping out all of Europe). In this world history, China and India dominate the globe, with Europeans as a minor footnote. It's a truly detailed portrait of the Earth that could have been, complete with a whole different set of revolutions, scientific advances, and epic world wars. Click here to buy.

'His Majesty’s Dragon' by Naomi Novak Amazon Look, sometimes you want an alternate history that doesn't hinge on genocide or Nazis. Sometimes you need a book that answers the burning question "What if Napoleon, but with dragons?" The Temeraire series is more of a fantastical, fun (but still smartly executed) take on alternate history, with dragons soaring high above the battlefields of the Napoleonic Wars. Click here to buy.

'And I Darken' by Kiersten White Amazon What if Vlad the Impaler had been a woman? Sure, it's not the most obvious "what if?" question about global history. But Kiersten White still manages to give one hell of an answer with And I Darken, a brutal, thrilling adventure starring the ferocious princess Lada Dragwlya and her struggle to take back her kingdom (while also getting some sweet revenge and catching some complicated feelings along the way). Click here to buy.

'The Calculating Stars' by Mary Robinette Kowal Amazon A meteor has taken out the majority of the 1950's U.S. government. What's to become of the space race now? The Calculating Stars imagines a higher stakes version of the 20th Century race to the stars (and beyond), with our heroine Elma York determined to join the mission as the first ever Lady Astronaut. Click here to buy.

'My Lady Jane' by Cynthia Hand, Brodi Ashton, and Jodi Meadows Amazon My Lady Jane dares to ask the question that has nagged historians for centuries: what if the historical Lady Jane Grey was married to a horse? This farcical send up of the Tudors rewrites English history to include some very silly things like shape-shifters, true love, and girls who read too many books. Lady Jane was a real historical figure, but in real life she was only queen of England for about nine days before she lost her head (quite literally). Click here to buy.

'The Alteration' by Kingsley Amis Amazon What if Martin Luther had decided he was cool with the Catholic Church as is? What if there was never a Protestant Reformation? Well, then the world might look something like the world of The Alteration, where the 1970s is frozen in the philosophy of the Middle Ages (which has a few perks and a whole lot of drawbacks). One young choir boy is coming of age in this world, where he may or may not be selection for the "alteration" process that will preserve his youthful voice forever for the sake of the church. Click here to buy.