William C. Kohler, M.D., was among the leading medical doctors practicing sleep medicine in the United States. A graduate of the University of Florida’s Medical School in Gainesville, Florida, he was board-certified in sleep medicine, pediatrics, and neurology (with special competence in child neurology). Dr. Kohler was also a trained, experienced user of hypnosis in medical treatment. As an approved consultant in clinical hypnosis with the American Society of Clinical Hypnosis, he was one of the earliest and most respected experts in this field. Dr. Kohler died only weeks after the complete manuscript was delivered to the publisher. Peter J. Kurz is a professional writer, translator, and photographer living in Pennsylvania, and co-authored Hypnosis and the Management of Sleep Disorders.