Professional personnel diagnostics is one of the most important investments in the performance of any organization. Diagnostic methods are used to find the best employees for the company and to optimally place them according to their competencies and inclinations. Personnel diagnostics also assists in analyzing individual and strategic development needs, as well as in the professional evaluation of change processes. In no other area of human resources can practical recommendations be derived so thoroughly from research as in personnel diagnostics. Although more than 800 scientific publications on the topic of personnel selection are published each year, the insights gained from research are rarely applied in practice. This book addresses this gap in an easily understandable manner.