The Diagnostic and Statistical Manual of Mental Disorders (DSM) provides a common language for mental health professionals and enhances the reliability of diagnoses; however, it does have its limitations. Notably, there is little basis for its current categorical representation of diagnostic entities. In this volume, Schmidt, Kotov, and Joiner present a much needed, alternative approach to developing the DSM taxometrics, an applied data-analytic tool that discerns categories from continua and establishes defining indicators of identified categories. Integrating the work of Paul Meehl and colleagues, the book begins the ambitious task of true diagnostics, that is, the application of taxometrics to psychopathological syndromes. In the book, the authors review what is known about the categorical nature of diagnoses, provide a user-friendly primer about taxometrics, and describe the methodology for applying taxometric procedures to diagnostic categories in the DSM. This provocative book will be of interest to any mental health professional who is committed to the refinement of diagnostic procedures.