Ryan Graudin is an American author known for her work in young adult fiction. She has written several popular novels, including The Walled City, which is inspired by the real-life history of a lawless city in Hong Kong. Her writing often blends elements of fantasy, history, and adventure. Graudin's books have received critical acclaim and have been nominated for various awards. In addition to The Walled City, she is also known for the All That Glows series and the Wolf by Wolf duology, which explores alternate histories and themes of identity and resilience.