Personality disorders have only recently been recognized as categories of psychiatric illness, and still need a sharper definition. This book interprets the personality disorders as products of the interaction between social influences and other etiological factors as part of a broad biopsychosocial model, and explains how personality traits develop into personality disorders. Strongly oriented toward recent empirical findings, the author argues that although biological, psychological and social factors are all necessary, none of them is by itself sufficient to produce a personality disorder. This basic model is also a model of treatment, in which the therapist addresses biological, experiential and social factors, and treatment recommendations focus particularly on social adjustment through the adaptive use of personality traits. Illustrated with revealing case vignettes, this balanced, humane and rational account of a difficult and sometimes contentious area will greatly assist clinicians in the understanding and treatment of individuals with personality disorder.