This book is designed to help students organize their thinking about psychology at a conceptual level. The focus on behaviour and empiricism has produced a text that is better organized, has fewer chapters, and is somewhat shorter than many of the leading books. The beginning of each section includes learning objectives; throughout the body of each section are key terms in bold followed by their definitions in italics; key takeaways, and exercises and critical thinking activities end each section.

Concern about psychology’s fragmentation is not new, but there has for the past decade been increasing calls for psychologists to acknowledge to the costs associated with fragmentation and to search for ways to unify the discipline. A New Unified Theory of Psychology introduces a new system that addresses psychology’s current theoretical and philosophical difficulties. The new theory consists of four interlocking pieces that together provide—for the first time—a macro-level view that clarifies the nature of psychology’s problems and offers a clear way to unify the various elements of the field. The unified theory provides the field of psychology with a well-defined subject matter, allowing both academic and professional psychologists will be able to develop a shared language and conceptual foundation.

Twenty years is a long time in the life of a science. While the historical roots of psychology have not changed since the first edition of this book, some of the offshoots of the various theories and systems discussed have been crit ically reexamined and have undergone far-reaching modifications. New and bold research has led to a broadening of perspectives, and recent devel opments in several areas required a considerable amount of rewriting. I have been fortunate in the last fifteen years to have worked with about 2,000 psychologists and other behavioral scientists who contributed to several collected volumes I have edited. As the editor-in-chief of the In ternational Encyclopedia of Psychiatry, Psychology, Psychoanalysis and Neurol ogy, I have had the privilege of reading, scrutinizing, and editing the work of 1,500 experts in psychology and related disciplines. In addition, I have written several books and monographs and over one hundred scientific papers. Armed with all that experience, I have carefully examined the pages of the first edition. Chapter 8 required substantial rewriting and several new sections have been added to other chapters: "Current Soviet Psychol ogy" (Chapter 2, Section 7); "New Ideas on Purposivism" (Chapter 5, Sec tion 4); "Recent Developments in the Sociological School of Psychoanalysis" (Chapter 9, Section 4); and "Present Status of Gestalt Psychology" (Chapter 12, Section 4). Chapter 15 was omitted, and two new chapters were added: Chapter 14 ("Humanistic Psychology") and Chapter 16 ("Selected Research Areas").

This comprehensive, scholarly text offers extensive biographical detail and full coverage of psychology's pre-19th century philosophical and scientific roots. The authors make connections between recent developments in psychometrics and biological, social, and cognitive psychology and their historical roots through current articles and references. This critical-thinking approach, combined with groundbreaking pedagogy, makes the text interesting and accessible to students and helps them understand the thinking processes that led to major psychological discoveries, as well as how they relate to contemporary specialty areas. Of the nearly 200 up-to-date references incorporated into the text, more than 100 are dated after 2000 and the remainder from 1990–2000. A timeline of notable psychological and historical events appears inside the front and back covers of the text for easy access. Timelines or chronologies for each chapter connect developments in psychology to world events in politics, science, and the arts. The text provides extensive coverage of women and minorities in a field dominated by Caucasian men.