This book explores the theoretical basis and state of the art of research on narcissism, Machiavellianism, and subclinical psychopathy. It also answers complex questions on the structure of the Dark Triad and its measurement for practical applications. Learn about how people high in these characteristics can, on the one hand, experience individual career success and show adaptive performance in specific fields and situations and, on other hand, present severe risks to others in the workplace with abusive and destructive leadership and counterproductive behavior. In addition, the author summarizes the legal and professional guidelines when assessing the dark personality characteristics of job applicants, examines the acceptance and social validity of such assessments, evaluates the available instruments, and makes recommendations for practical applications and further research. With the focus on practical applications, the book presents the development, quality, and application of a test to capture the Dark Triad in the workplace designed for use in organizations. Concrete recommendations are given on how to use the characteristics narcissism, Machiavellianism, and subclinical psychopathy in personnel selection. Researchers and practitioners interested in applying the dark triad in personnel work will find this book full of valuable information on how to undertake legally compliant processes and how to utilize the great potential the Dark Triad personality characteristics have in making decisions on aptitude.