The textbook provides a compact and easily understandable introduction to the fundamentals of Clinical Psychology. Clinical Psychology is the most important application area of psychology. With its conceptual models, it draws on numerous findings from basic psychological disciplines while also conveying the necessary knowledge for the professional fields that build upon it, including hospitals, practices, and rehabilitation clinics. This textbook presents the required foundations through selected examples. Additionally, it addresses basic concepts of Clinical Psychology, such as the fundamentals of classifying mental disorders, disorder models, clinical diagnostics, and statements regarding the need for treatment for mental disorders. Questions of epidemiology and healthcare research are also discussed.