These days, if you ask any woman under the age of 24 what book she has on her nightstand, the answer is very likely to be a romantasy by Sarah J. Maas.

“Romantasy”—a portmanteau of “romance” and “fantasy” (think Bridgerton meets The Lord of the Rings)—exploded in popularity during the pandemic, largely due to the rise of the social-media reader community BookTok. Maas, who had already published 13 romantasy books by 2020, became an overnight phenomenon. Her books set up camp at the top of the New York Times best-seller list and have remained there ever since. She’s basically the Taylor Swift of publishing.

Maas, now 38, started writing her first book when she was 16 years old. Ten years later, the finished book—titled The Throne of Glass—was picked up by Bloomsbury and published in 2012. Maas has since written 15 more novels and become one of Bloomsbury’s best-selling authors, alongside J. K. Rowling.

Her latest book, House of Flame and Shadow, came out in January to much fanfare and sold 360,000 copies in one week in the U.S. alone. According to a recent Forbes report, Maas is currently the best-selling author of 2024. To date, her books have sold more than 38 million copies globally.

This is surprising for many reasons, the first being: Since when do young women like fantasy?

She’s basically the Taylor Swift of publishing.

It used to be that the big fantasy franchises—The Lord of the Rings, Game of Thrones, The Dark Tower—had legions of nerdy male fans who did things such as learn Elvish and take to Reddit to debate when George R. R. Martin would finally release The Winds of Winter. (It’s been 12 years, if anyone’s still counting.) Now it’s armies of teenage girls making fan-casting TikToks.

The answer to that question may lie in the second reason, which is that these books are straight-up filthy. The Financial Times described Maas’s fantasy world as a “JRR Tolkien-esque universe populated by sexually charged fairies.” That’s putting it lightly. The fantasy part of romantasy has certainly taken a back seat in Maas’s books, and the romance bears far more of a resemblance to Anastasia Steele and Christian Grey than to Aragorn and Arwen.

The true secret of Maas’s success lies in her adherence to a core set of romantasy tropes. Follow them and you’ve got a golden ticket to the front window of every bookstore:

1. A female protagonist who is no older than 20 but no younger than 17. She is visibly malnourished, but in a cute way where she is skinny but still outrageously beautiful.
2. Despite her severe lack of personality, a prophecy decrees that she will be greater and more special than everyone else.
3. A ravishingly handsome male love interest who speaks only in growls and purrs and is perpetually horny. He looks like the love child of Orlando Bloom’s character in The Lord of the Rings and Satan. He is usually the “fated mate” of the female protagonist. (Lucky her!)
4. All names must be unnecessarily hard to pronounce. See: Feyre (fay-ruh), Chaol (kale), and Rhysand (ree-sand).
5. There must be at least one extremely long and graphic sex scene that would make the people riding the subway with you deeply uncomfortable. Wings will be involved.
6. The book title must follow the formula of “Kingdom”/“Court”/“Throne”/“House” + Weather Phenomenon + Vaguely Ominous Noun. Something like “House of Storm and Blood,” “Court of Fire and Shadow,” or, perhaps, “Kingdom of Coastal Flooding and Doom” (copyright pending).
7. To meet fantasy-genre compliance rules, the book must begin with an extremely basic map that no one will use or reference at any point.
8. For plot reasons, there must also be an all-powerful, supernatural villain intent on destroying the world.
9. Sexy elves never hurt.

Under the artful hand of a master such as Maas, these elements combine to make a highly entertaining, extremely bingeable best-seller series. It’s a formula that’s proven capable of captivating an entire generation of women.

A day may come when her devotees tire of her muscle-bound fairy lords, oversexed elves, and aroused werewolves, but for now, it’s Maas’s world.

Paulina Prosnitz is an Associate Editor at AIR MAIL