First published in 1968, Ninian Smart's The Yogi and the Devotee: The Interplay Between the Upanishads and Catholic Theology is based on lectures given in Delhi and explores in a novel way the relation between Hinduism and Christianity. The author puts forward a general theory of the relationship between religious experience and doctrines, a theory he had developed in earlier works. He argues that a new form of "natural theology' should be presented, which would show the relevance of religious experience and ritual to what is given in revelation. Smart believes this could be the key to a new understanding between Christianity and Indian religions, and also examines what Christians can learn from other faiths. During a career as a Professor of Religious Studies and Philosophy, Ninian Smart was hugely influential in the way Religious Studies was taught, not only in Britain but around the world.