There is no ideal analgesic and the most potent drug is not always the best because of its side-effects. Non-opioid analgesics, including the non-steroi- dal anti-inflammatory drugs and the non-narcotic analgesics, play an im- portant role in the relief of a wide spectrum of painful conditions, though they vary in efficacy and safety. This book reviews the role which non-opi- oid analgesics play in the relitff of pain, particularly with regard to post- operative and cancer pain. Emphasis is placed on the clinical indications for the non-acidic analgesic, dipyrone, and its relative safety in comparison to other non-opioid anlgesics. Michael J. Parnham 9 Introductory remarks Klaus A. Lehmann, Department of Anaesthesiology and Operative Intensive Care, University of Cologne, J osef-Stelzmann-Str. 9, D-50924 Cologne, Germany Opioids are considered to be the most potent analgesics for the manage- ment of acute and chronic pain. Much progress has been achieved with respect to their general availability in most countries, and health care per- sonnel have been encouraged to use these drugs more generously in a vari- ety of pain syndromes, including post-operative or cancer pain.The intro- duction of new techniques such as Patient-Controlled Analgesia (PCA) or guidelines such as the WHO ladder concept for cancer pain mangement have considerably increased our knowledge of their benefits and prob- lems.