Psychological and psychosomatic-related sick leave is rising rapidly. What can occupational physicians, company doctors, businesses, and cost bearers do about it, and where can they start? They are not primarily trained to deal with psychological issues. The contributions in this book fill this gap and are tailored to their needs. On one hand, it provides a solid scientific foundation, and on the other hand, it offers practical solutions for workplace practice. Part 1 outlines and discusses the current scientific knowledge: work-related psychosocial influences, models of work stress, and methods for investigating the connections with employees' mental health. This includes assessing illness risks, identifying occupational groups with increased risks, and understanding the bio-psycho-social relationships.