Diagnostic assessment methods are used in all areas of psychology. This volume provides insight into the workings of psychological diagnostics. After establishing a baseline for diagnostic assessment methods, the central application areas of intelligence, developmental, and personality diagnostics are introduced. The subsequent chapters address clinical-psychological and educational-psychological diagnostics, as well as approaches and procedures in suitability diagnostics, neuro- and legal psychology diagnostics, and rehabilitation diagnostics. The chapters describe the tasks and goals of diagnostics in their respective application areas and present the diagnostic approaches and central questions. An overview of the diagnostic process and suitable assessment methods is provided.