This first Handbook on Psychological Injury and Law covers a vast array of topics, and the general foci of the field are highlighted in this first chapter of the book. The chapter defines the term psychological injury and gives multiple ways that forensics, the law, and court are implicated in the working of the field. Psychological injuries are generally contentious in court because they can be coached or otherwise subject to exaggeration and conscious malingering for monetary gain. They include the diagnoses of posttraumatic stress disorder (PTSD), chronic pain (somatic symptom disorder with predominant pain), and mild traumatic brain injury (MTBI), with Major Depressive Disorder and multiple comorbidities also common. Psychological assessors need to conduct comprehensive, scientifically informed, and impartial assessments for their proffers to court, and this especially refers to using testing instruments that include validity tests and scales on plaintiff credibility, for example, assessing test performance and symptom validity. This introductory chapter lists five common themes that cut across all the chapters in the book. The Handbook will serve the field well and should be indispensable for research, practice, and court.