The main aspects of developmental psychology can be found in Section I; it includes the concept of attachment, which is a central construct of developmental psychology that has gained more and more importance in clinical psychology and psychotherapy over the years. Neuropsychological disorders, which play a central role in many other psychological disorders (e.g.: executive functions, learning difficulties, dyslexia), are addressed in a separate chapter. Section II (Diagnostic and Clinical Psychology) focuses on different facets of diagnostics, with diagnostic key aspects in clinical psychology. The connection between the construct of attention and mindfulness therapy exemplifies the transfer into concrete therapeutic approaches. Furthermore, important considerations in connection with differential diagnostics will be addressed by means of disorders, which have only come into focus during recent years. These disorders include autistic spectrum disorders and adult ADHD (attention deficit/hyperactivity disorder) as well as burn out syndrome. The complexity of clinical psychology shall be illustrated by means of some examples in Section III (Clinical Psychology and Other Disciplines). In the last chapter, a more practical approach is applied. For the clinical psychologist, the vast amount of empirical studies and clinical relevant results bear the problem of accomplishing them and putting them into practice. Here, a continuous education is essential.