Avatar, Book One is a Star Trek: Deep Space Nine novel by S.D. Perry published by Pocket Books in 2001, the first novel in the Avatar duology and the first book in the post-television finale run of DS9. The duology introduces several important characters and centers around a Jem'Hadar attack on Deep Space 9 and the discovery of a Tear of the Prophets. The duology was reprinted in the omnibus Twist of Faith in 2007.