would like to introduce this encyclopedia of psychology by focusing on both twenty-first century and more distant historical contexts, while additionally highlighting the scope and depth of the work of psychologists, their students, and their supporters. As reading these volumes will show, psychology is a diverse and large field. It is also a science. I remind readers that most of the research described in these volumes is completed through the silent contributions of tens of thousands of volunteers as well as nonhuman animal participants. Without such contributions, none of this knowledge would be possible
