Thou Art That is a book by Joseph Campbell exploring the mythological underpinnings of the Judeo-Christian-Islamic tradition. It was edited posthumously from Campbell's lectures and unpublished writing by Eugene Kennedy.

Published by New World Library in 2001, Thou Art That was the first title in the Joseph Campbell Foundation's Collected Works of Joseph Campbell series.

• Campbell, Joseph (2001). Thou Art That: Transforming Religious Metaphor. Novato, California: New World Library. ISBN 1-57731-202-3.

• Thou Art That page on the JCF site