The first two seasons of Netflix’s Stranger Things were a cultural phenomenon, and there’s been plenty of tie-in merchandise to go along with it. Now, that’ll include a handful of books — including a prequel novel, authored by Gwenda Bond, which will follow the story of Eleven’s mother and her entry into the MKUltra program, according to Deadline.

Penguin Random House will publish a series of books based on the series. The first two will hit bookstores this fall: a gift book aimed at younger readers with “advice, wisdom, and warnings from the Stranger Things world,” and a behind-the-scenes book, Stranger Things: World Turned Upside Down: The Official Behind-The-Scenes Companion.

Bond’s novel will be available next spring. It doesn’t have a title yet, but it will follow Terry Ives, who appeared in the show’s first season. During that debut season, we learned that she joined Project MKUltra, supervised by Dr. Martin Brenner, and was experimented on with drugs before giving birth to a daughter, Jane, who was taken by the program. When Terry attempted to take her daughter back, she was tortured by Brenner and left in a vegetative state. Bond says we’ll see Terry’s’ “intersection with the MKUltra program” and that we’ll “get to know and love her in a whole new way.” She also says that she’ll be coming up with her own epic, 1960s and 1970s-themed playlist to accompany it.

It's about Eleven's mother Terry and her intersection with the MKUltra program and you're going to get to know and love her in a whole new way. I'm SO EXCITED. — Gwenda Bond (@Gwenda) June 8, 2018

Deadline says that Bond’s novel will be followed by additional books for adults and children. Building out from media properties is something that Penguin Random House is known for. (It’s also the publisher that has the license for the Star Wars franchise, and it has been working closely with Lucasfilm and Disney to flesh out the world between the new crop of films, comics, and video games.) Bond is also no stranger to tie-in fiction: she’s authored a series of novels about Superman character Lois Lane.

Given the popularity of Stranger Things — and its connections to the works of horror author Stephen King — a series of novels seems like a sure bet. It’s a way to provide some additional stories to the various parts of the show that were hinted at but won’t likely be reexamined in the television show. A book series could also be a way to continue the franchise after the TV show ends, which its creators have pegged to last for four or five seasons. Plus, it’ll give devoted fans of the franchise something to read while they wait for the third season, which likely won’t begin streaming until next year.