This scholarly book reviews the validity of clinical judgments, as shown by more than 1,000 controlled studies of assessments of personality and psychopathology, psychodiagnosis, case formulation, behavior prediction, treatment planning, and neuropsychological assessment. Although written primarily for psychologists, Studying the Clinician is certainly relevant to psychiatric practice. The difficulties in evaluating judgment validity are clearly expounded. In behavioral predictions and treatment planning, validity analyses are possible because outcome yields a predictive test. However, the correctness problem is vexing for personality, psychopathology, diagnostics, and causal judgments.