Charles T. Tart, PhD, is emeritus professor of psychology at the University of California, Davis, as well as the Institute of Transpersonal Psychology. Here he discusses a number of altered states including marijuana intoxication, dreaming, hypnosis, and out-of-body experiences. He describes his concept of “state specific research” using lucid dreaming as a clear example. Excerpts from the film, Altered States, with actor William Hurt are shown as they refer to Tart and his work. He also reviews the significance of altered states of consciousness for psychology in general as well as for our understanding of spirituality and the soul. He suggests that different states of consciousness are like different tools, each with unique capabilities.