In the upcoming fifth edition of the American Psychiatric Associations Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the major innovation for the personality disorders will likely be a shift from the classic syndrome-based approach to a dimensional description approach. This book explains how personality disorders can be understood from the perspective of the Five-Factor Model (FFM), the most heavily researched and empirically supported dimensional model of general personality structure. Since the second edition of this authoritative text was published in 2002, the research base supporting the FFM has more than quadrupled. As a result, the vast majority of this volume is new. The chapters summarize the conceptual and empirical support for the FFM, including the dimensional description of specific personality disorders and the application of the model for assessment and treatment. Case studies are also provided.