Therapeutic Trances: The Cooperation Principle in Ericksonian Hypnotherapy, by Stephen G. Gilligan, is a signed hardcover book published in 1987 by Brunner/Mazel, Inc. This advanced-level textbook, specifically focused on the topic of hypnotism, delves into the psychological aspects of therapeutic trances and offers insights into the cooperation principle in Ericksonian hypnotherapy. With 366 pages of content, this book is a valuable resource for adult education and further education students studying psychology and hypnotism.