Pain is a symptom of many clinical disorders, afflicts a large proportion of the population and is largely treated by pharmacological means. However, the two main classes of drugs used are the opioids and the non-steroidal anti­ inflammatory drugs, drugs that have a long history. The last decade has seen remarkable advances in our understanding of some of the pharmacological bases of pain and analgesia and this book aims to reflect these rapid changes in our understanding of pain mechanisms. One impetus to these scientific advances has been dialogue and interactions between scientists and clinicians; as a result we now has a number of animal models of clinical pain states, to mimic certain aspects of clinical pathophysiological pain states. Molecular aspects of receptors and the synthesis of tools for probing receptor function have also been rapid growth areas. A number of controlled clinical studies using novel licensed drugs have also resulted from recent research, offering hope to certain patients with severe intractable pain. However, we desperately need the pharmaceutical industry to develop new drugs based on these novel targets for analgesic therapy. This book attempts to provide an overview of the important areas of the pharmacology of pain. This book, although providing an account of the pharmacology of pain transmission and its control based on the underlying anatomical organization and physiological responses, does not attempt to cover these latter two areas.