Throne of Glass is a high fantasy novel series by Sarah J. Maas, following the assassin Celaena Sardothien in a world where magic has vanished, as she competes to win her freedom from a tyrannical king and uncovers a dark conspiracy. The series includes eight main books, with The Assassin's Blade serving as a prequel, and is known for its epic scope, romance, and action. 

High fantasy with elements of romance and adventure. 

This is the first book in the 8 book series.