PREFACE There has not been an edition ofA History of Modern Psychologysince 1994, while there have been two new editions ofA History of Psychologyin the same period. I have incorporated into this third edition all the relevant changes fromA History of Psychology,without reducing this book's expanded coverage of contemporary psychology. The most obvious new features of this edition are structural. I have included a new Chapter Two that summarizes the history of psychology from the Renaissance and Scientific Revolution up to the middle of the nineteenth century. In writing these chapters, I have drawn not only fromA History of Psychologybut from a paper, "Mind as scientific object: An historical-philosophical exploration," written forMind as Scientific Object(D. Johnson & C. Erneling (Eds.), Oxford University Press, in press), and two articles, "The Renaissance through the Eighteenth Century," and "The Nineteenth Century through Freud," for theAPA Encyclopedia of Psychology(Oxford University Press, 2000). Chapters 3 to 7 on the founding of psychology and the conspiracy of naturalism have been updated, the most notable change being to Chapter 4, The Psychology of the Unconscious, which is now organized temporally rather than topically. The treatment of psychology in the twentieth century has been both updated and re-organized to provide a clearer focus on each of the two strands of modern psychology: scientific psychology and professional psychology. Chapters 8 to 10 tell the story of the scientific study of the mind in the twentieth century up to about 2000. Chapters 11 to 13 tell the story of professional psychology in the same years. This structural change reflects two concerns of mine. First, in my own teaching I have found that shuttling back and forth between very different narrative strands that happen to occur in the same time period confuses students. I think the pictures of both scientific and professional psychology become clearer by telling each story separately. Secondly, as a number of observers have pointed out, scientific and professional psychology are increasingly going their separate ways despite occasional protests, and my separation of the two narratives reflects what I believe is historical reality. Finally, separating the material should make it easier for teachers to emphasize one or the other topic. As always, I would be happy to hear any comments from professors or students aboutA History of Modern Psychology,Third Edition. Please email me at firstname.lastname@example.org . THOMAS HARDY LEAHEY Richmond, VirginiaLeahey, Thomas H. is the author of 'History of Modern Psychology', published 2000 under ISBN 9780130175731 and ISBN 0130175730.