It's more common for books to be turned into movies and series but in the case of Netflix's most popular sci-fi show Stranger Things there are no rules. According to Deadline, the show is currently being fixed to be turned into a book that will come out this Fall. There will be two book options - one that is a behind the scenes telling (“Stranger Things: World Turned Upside Down: The Official Behind-The-Scenes Companion") while the other is hardcover for young readers.
Once the two titles make the rounds author Gwenda Bond will release a prequel novel on Eleven’s mother and the MKUltra program that will drop in 2019.
As for the upcoming season three, we've been collecting a good amount of data for a while now that has prepared us for the next chapter. "We’re not going to put Will through hell fora third season in a row," executive producer Shawn Levy previously stated. "He’ll be dealing with stuff, but he won’t be at rock bottom the way we forced the amazing Noah Schnapp to play.”
More recently we learned that a new lead will be added to the show by the name of Maya Hawke. She'll play an “alternative girl” who is bored with her mundane day job. Things get more exciting when she discovers a dark secret in Hawkins.