Thus far, Maas has written five novels and a collection of novellas set in the Throne of Glass universe. According to Hypable, Kira Snyder will serve as the screenwriter for this adaptation project. Anna Foerster has signed on to direct the pilot episode.
Here’s more from Deadline: “Queen of Shadows follows Celaena Sardothien, a complicated female assassin with a mysterious past who only wants her freedom. Now beholden to an increasingly tyrannous king, Celaena will become a reluctant hero against the multitudes of forces that threaten to destroy her world. Along the way she will make friends, enemies, and lovers, and be wildly underestimated by all of them.” (via A.V. Club)