The World Health Organisation published 'Cancer Pain Relief' in 1990, advocating simplicity in the choice of analgesic and of route of administration. Since that time an increasing number of opioids for moderate to severe pain in an increasing number of formulations have become available, making professionals' choices about cancer pain management more complex. Part of the Oxford Pain Management Library, this book compares and reviews the current opioids for moderate to severe pain and considers their place in the management of cancer pain, using morphine as the accepted 'gold standard' worldwide. The first sections of the book deal with the principles of pain management in cancer pain and the range of treatments available for pain due to cancer. Chapters on opioid pharmacology, starting and titrating opioids and managing their adverse effects are followed by discussion about talking to the patient commencing opioids for moderate to severe pain. Sections also include current evidence around opioid prescribing in patients with liver and renal impairment, respiratory disease or a history of substance misuse. This book presents current evidence in a clinically-based, practical and applicable way, so that the book is useful for all healthcare professionals caring for patients with pain due to cancer.