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.