If you’ve paid any attention to the fantasy fiction section of your local bookstore, you’ve probably heard of Sarah J. Maas. Her books have sold over 13 million copies, she’s a fixture at the top of the New York Times bestseller list, and her complex stories have given rise to the sort of rabid fandom that lends itself to eager YouTube discourse, complicated reader theories about its characters and larger universe, and a bustling Etsy economy of assorted themed fan-made products. People that love Maas’s books, love her books. People who don’t love her books…probably just haven’t read them yet.

Though her first series, Throne of Glass, was published in 2012, it wasn’t until her second, A Court of Thorns and Roses began in 2015 that she became a crossover sensation. Thanks to its feisty heroine, its Beauty and the Beast-inspired narrative framing, and the rich,...