In the last two decades, mentoring programs have experienced a tremendous upswing. They are now considered the most effective individual support method in both the workplace and educational settings. However, until now, there has been a lack of a textbook in the German-speaking world that systematically addresses the theoretical background and presents the current empirical research status as well as prototypical applications. In the 16 chapters of the book, findings and practical projects related to mentoring in schools, youth work, higher education, and professional settings are presented following a theoretical introduction. Another focus is on e-mentoring.