That pain is a serious clinical problem, which requires considerable effortsby physicians and the nursing staff, has been stressed in numerous publications. Transdermal application is well known for a variety of drugs, including cardiovascular drugs, antiemetics and hormones. Some years ago, first experience was also made with transdermally administered opiates from which the transdermal therapeutic system (TTS) fentanyl has now been approved by the American Food and Drug Administration. The book presents the results of the first international workshop "Transdermal Fentanyl," held September 27 -28, 1990 in Cologne, FRG. This workshop was intended to facilitate a critical evaluation of theoretical and clinical studies with the new, non-invasive fentanyl application and to provide an opportunity for an exchange of ideas about its value for pain management, anaesthesiology and future investigations in this field. Topics covered by the book are physiology of transdermal permeation, experience with other transdermal systems, the present state of acute and chronic pain management and experimental and clinical studies with transdermal fentanyl, with special concern to analgesic efficacy and side effects. Readers will easily find out that the experts appreciated transdermal analgesia but also warned against an uncritical optimism. TTS fentanyl can be a valuable tool in the clinicians' armentarium against pain. It should be kept in mind, however, that it represents a new administration mode, not a new drug, and that the sustained, non-invasive application requires well reflected diagnosis and good general standards of pain management.