This monograph contains the results of an interdisciplinary study into the life histories of male delinquents. Conducted by the Institute of Criminology at the University of Tübingen, it compares the biographies of young adult inmates with a random sampling of young men from the general population and considers the results in the light of other studies of a similar nature, primarily from the Anglo-American literature. The significance of this study lies not only in the data presented, but also in the conclusions the author draws concerning subject matter and methods of criminology as an autonomous, integrated science. This leads to a practice- oriented applied criminology based on the evaluation of specific criminological criteria. For the practitioner, such an approach allows a differential assessment of the individual offender in the context of his social relationships with conclusions regarding prognosis and therapeutic effects.