This book specifies the changes in the personalities of managers in the process of using coaching. It emphasizes the scientific dimension in the context of the issue of coaching, offering a multidimensional concept of coaching and verifying a new methodology for the assessment of coaching effects on managers' personality types based on a holistic approach.The text is about real science, the latest scientific findings, and real research on the assessment of coaching effects on managers' personality types and behaviour so that they can respond to the changes and challenges they face in a more effective and professional way.