Psychology and Criminal Justice covers the ways that psychology intersects with the criminal justice system, from explaining criminal behavior to helping improve the three criminal justice pillars of policing, courts, and corrections.The book is divided into two parts. The chapters in Part One describe how different areas of psychology can help us understand why people commit crimes. The Basics of biopsychology, developmental psychology, behavioral psychology, social psychology, personality psychology, and psychopathy are presented first in their respective chapters. These initial chapters conclude with a section called Explaining Criminal Behavior that applies The Basics to help explain criminal behavior. Part Two of the textbook begins with a chapter on three topics in psychology that are particularly relevant to the criminal justice system: mental illness, trauma, and substance use. In the remainder of Part Two, there are two chapters each for policing, courts, and corrections. Each of these chapters discusses the ways principles from psychology can help with criminal justice processes, including police investigations and officer mental health, psychological evaluations for court proceedings, juror selection and decision making, behavior change, and the effects of imprisonment.After decades of overreliance on sociology-based theory and research, the field of criminal justice is looking to psychology for explanations and insight. This book is essential reading for upper-level undergraduate and graduate-level courses housed in both criminal justice and psychology departments.