Holly Black is an American writer and editor who is probably most well known for writing The Spiderwick Chronicles. She has also written several other books, including Modern Tales of Faerie, The Good Neighbors, and The Curse Workers.
Inspired by a childhood immersed in fairy tales, most of her books feature the supernatural and The Fair Folk. Not always portrayed so positively, either--the supernatural creatures in her stories are usually of the cruel, vindictive, yet terribly beautiful variety. Her young adult works also have a generous helping of Body Horror and Gorn.
She's good friends with Cassandra Clare.