Psychologists offer an increasing variety of services to the public. Among these services, psychological assessment of personality and behavior continues to be a central activity. One main reason is that other mental health professionals often do not possess a high level of competence in this area. And when dealing with children and adolescents, psychological assessment seems to take on an even greater role. Therefore, it follows that comprehensive graduate-level instruction in assessment should be a high priority for educators of psychologists who will work with these youth. This textbook is organized into three sections, consistent with the authors’ approach to teaching. Part I provides students with the psychological knowledge base necessary for modern assessment practice, including historical perspectives, measurement science, child psychopathology, ethical, legal, and cultural issues, and the basics of beginning the assessment process. Part II gives students a broad review of the specific assessment methods used by psychologists, accompanied by specific advice regarding the usage and strengths and weaknesses of each method. In Part III, we help students perform some of the most sophisticated of assessment practices: integrating and communicating assessment results and infusing assessment practice with knowledge of child development and psychopathology to assess some of the most common types of behavioral and emotional disorders in youth.