This book has been written for the general health care professional, from every medical and paramedical specialization. Because pain is the most common factor driving patients to seek professional advice, it is likely that every physician, psychologist, and therapist has been clinically exposed to the difficulty and the frequent frustration of dealing with people in pain. All of them may find in this book some explanations for their puzzles and some updated information, which usually are published in specialized journals not ordinarily read by the general practitioner. Actually the book has been addressed to professionals at two different levels of general practice. At one level is the busy practitioner who treats most patients with' 'acute" pain, and who may use this information in daily practice to prevent the onset of chronic pain; a common effort from all professionals currently is needed to curb the "epidemic" of chronic pain in the United States. At another level the book has been addressed to the practitioner who may have a more intense desire to become involved in the actual management of chronic pain patients.