This Handbook provides a contemporary and research-informed review of the topics essential to clinical psychological assessment and diagnosis. It outlines assessment issues that cross all methods, settings, and disorders, including (but not limited to) psychometric issues, diversity factors, ethical dilemmas, validity of patient presentation, psychological assessment in treatment, and report writing. These themes run throughout the volume as leading researchers summarize the empirical findings and technological advances in their area. With each chapter written by major experts in their respective fields, the text gives interpretive and practical guidance for using psychological measures for assessment and diagnosis.