The fully revised and updated second edition of this well-established reference is an exhaustive guide to the key terms used in psychological testing, assessment and measurement. Over 3000 definitions offer clear explanations of statistical procedures commonly used in psychology; major psychometric and other psychological tests; categories of mental illness, mental disability, and brain damage; frequently used medical terms; basic neuroanatomy; and types of psychological therapies.This book is suitable for all levels of understanding, from undergraduate and postgraduate students to practitioners of psychology and associated fields.