The Great Tree of Avalon is a fantasy novel by T. A. Barron, published by Penguin Young Readers Group. The book is the ninth novel in the 12-book series known as Merlin Saga. It was originally published as The Great Tree of Avalon: Child of the Dark Prophecy, the first novel in The Great Tree of Avalon trilogy, and is set in a world made up of a great tree and its seven roots inhabited by creatures.