William A. Henkin, Ph.D., is a licensed Marriage and Family Therapist and a Board Certified Sex Therapist. He is author or co-author of more than a dozen books, including The Psychic Healing Book (with Amy Wallace), Bodywise (with Joseph Heller), The Spiral Tapestry, The Rocky Horror Picture Show Book, and Consensual Sadomasochism: How to Talk About It and How to Do It Safely (with Sybil Holiday). He conducts his private psychotherapy practice in San Francisco.