Dark personality traits, and traits with dark features, are connected to destructive behaviors and interpersonal problems. Even moderate levels of these traits can cause significant issues. Understanding them will play an integral role in treating individuals who exhibit dark, unhealthy characteristics. Thus, a primary goal of this book is to unite personality psychology and clinical psychology. It synthesizes recent research that connects pathological personality features to the Big Five personality dimensions, creating an interdisciplinary taxonomy of dark personality traits. This volume brings together a diverse panel of experts who provide complex, nuanced perspectives on a variety of personality traits, including those that are readily accepted as dark (e.g., the Dark Triad of narcissism, psychopathy, and Machiavellianism), have been largely ignored by the broader psychological literature (e.g., spitefulness), have not been included in previous discussions of dark personality traits (e.g., authoritarianism), or appear to be at least somewhat positive on a superficial level (e.g., perfectionism and fearless dominance). Chapters explore both maladaptive and adaptive features of these traits, including how to address them in clinical settings. The final chapter ties the entire volume together with a thorough review of common themes, clinical implications, and research goals across all traits.