Unlike an encyclopedia, the volumes in this set can stand alone as state-of-the-field handbooks. Together they cover both the science and the practice of psychology broadly and in depth. Each volume has its own editor(s) and contains some two dozen articles by experts who write well for an audience intended to include graduate students in behavioral science, professional psychologists who need a refresher course in their own specialty and/or an introduction to others, and educated readers outside of psychology who want to delve into it. Organized with great care, the set has a logical integrity unified by two threads: the history and evolution of each topic and the importance of research.