The study of drug use and drug effects is fast moving and exciting; it is a rapidly expanding field where new developments, discoveries, and insights are happening every day. Perhaps one of the more exciting aspects of drug research is that it is truly multidisciplinary, encompassing pharmacology, neuroanatomy, neurophysiology, epidemiology, endocrinology, psychology, and more recently, economics, to name a few. This text is primarily about the application of behavioral research (traditionally referred to as psychology) to understanding the effects of drugs and the use of drugs. Because the field is made up of so many disciplines, it is impossible to consider the role of behavioral science in isolation. In this book, the role of behavioral research is placed in the context of the contributions of these other disciplines. Within the last few years, most of the serious advances in drug research have been made in the area of psychology and neuroscience as it applies to understanding why people and other animals use drugs. These advances were discussed in the fourth edition. In this, the fifth edition, attention has been shifted back to the drugs currently being used. A whole new chapter has been added that discusses the inhaled solvents and anesthetics, and other chapters have been updated to include a discussion of other substances whose use has expanded in recent years. These include a discussion of "club drugs" such as dextromethorphan covered in the chapter on opiates, ecstasy and ketamine in the hallucinogen chapter, and flunitrazepam (Rohypnol) and GHB in the benzodiazepine chapter. The chapter on barbiturates and benzodiazepines has been shortened, and now concentrates primarily on the benzodiazepines to reflect the changing patterns of use, both medical and illicit, of both these drugs. Like the fourth edition, the fifth edition does not have a glossary. I have attempted to design the index to fill the function of a glossary. You will notice that for the entries for important concepts that previously would have been in a glossary, the page of the definitive discussion of the concept is indicated in bold print. This should permit the student to locate instantly the appropriate definition of any concept as well as a more extended discussion of it, not just a cursory and necessarily constrained glossary definition. This book would not have been possible without the assistance of marry people. These include those mentioned in the earlier editions. In this edition, I would like to acknowledge the help of my wife Edna McKim who not only assisted with many technical matters but tolerated my absence, both physical and mental, while the book was being written, my colleagues, both at Memorial University and many other institutions around the world who read many drafts, sent me manuscripts, pointed out many errors and made many suggestions, my students who suffered through many teaching experiments and nearly unreadable drafts of the manuscript, and the technical and office staff in the Psychology Department at Memorial University. All these people include, but are not limited to Rob Brown, Geoff Carre, Marilyn Carroll, Jamie Drover, Harriet de Wit, Shola Elabanjo, Kim French, Carolyn Harley, John Harvey, Peter Heinen, Gene Heyman, Julia Lang, Bow Tong Lett, Gerard Martin, Paul Mattless, James S. MacDonall, Andrew McKim, Edna McKim, Heather McKim, Kathleen McKim, Brenda Noftle, John Podd, Sam Revusky, Brandi Smith, John Scott, Bernice St. Croix, Bernie Weiss, Bill Wolverton, and Jim Zacny. I would also like to acknowledge the helpful comments of Cheryl Kirstein, University of South Florida; John M. Morgan, Humboldt State University; Raymond Sanchez Mayers, Rutgers University; Daniel J. Calcagnetti, Farleigh Dickinson University; and Tom Byrne, Massachusetts College of Liberal Arts who reviewed this manuscript for the publisher. Apart from taking credit where such is due, none of these people caMcKim, William A. is the author of 'Drugs and Behavior An Introduction to Behavioral Pharmacology', published 2002 under ISBN 9780130481184 and ISBN 0130481181.