Robert Ellwood is the author of over twenty books, ranging from textbooks in religious studies (including Many Peoples Many Faiths, a popular world religion textbook) to books of religious history (The Fifties Spiritual Marketplace, The Sixties Spiritual Awakening, and Islands of the Dawn, among others). He was a professor of world religions at the University of Southern California for thirty years, from 1967 until his retirement in 1997.