This book contains a manual for the process of clinical assessment in mental health care. All phases in the process are described and discussed, from referral to classification and explanation up to the indication for treatment. A running case example illustrates the steps and considerations in each phase. The book is written for students as well as practising clinicians. Assessment is seen as a form of decision making under uncertainty, and insights from psychological decision making studies are presented and translated to the clinical situation, often in examples given by clinicians-in training. The book integrates knowledge from research and from clinical practice into a guideline for the assessment process that helps clinicians perform the interesting and demanding task of clinical assessment in a structured way. Cilia Witteman, PhD, is full professor of Psychodiagnostic Decision Making at the Behavioural Science Institute of the Radboud University, Nijmegen (The Netherlands). She studies clinical assessment processes and clinicians making diagnostic decisions. She teaches assessment and psychometrics to clinical psychology and special education students as well as to postmaster clinicians. Paul van der Heijden, PhD, works as licensed clinical psychologist and CBT therapist at the Centre of Adolescent Psychiatry, Reinier van Arkel Mental Health Institute ‘s-Hertogenbosch (The Netherlands). He teaches clinical assessment at the Radboud Center for Social Sciences and studies personality assessment at the Behavioural Science Institute, Radboud University, Nijmegen (The Netherlands). Laurence Claes, PhD, clinical psychologist and licensed CBT therapist, is full professor at the KU Leuven, Faculty of Psychology and Educational Sciences as well as at the University Antwerp, Faculty of Medicine and Health Sciences (Belgium). She teaches clinical assessment. Her research focuses on the association between personality and psychopathology (eating disorders, non-suicidal self-injury, and compulsive buying).