This handbook provides up-to-date summaries and applied recommendations for psychological assessment and diagnosis. The comprehensive compilation of chapters written by experts in their respective fields should guide graduatelevel teaching/training and research as well as serve as an update on assessment for behavioral health service providers. Each chapter presents major theoretical, empirical, methodological, and practical approaches used in psychological assessment and diagnosis across different assessment methods, varied psychological disorders/ presentations, and unique assessment settings. As will be seen when reading the chapters, a major theme for empirically based assessment is that test users must “read well beyond the manual” to decide whether to use and how to interpret any psychological test or measure (Holden & Fekken, Chapter 23, this volume, p. 322).