'Hopeless Criminals and Habitual Offenders. The Detection of Early Crime in the Scientific Work of Friedrich Schaffstein (1905-2001)': The study deals with the criminal lawyer Friedrich Schaffstein, his biographical career and his influence on German juvenile criminal law in the 20th century. A focus is placed on his research project to be able to scientifically predict criminal behaviour of young people, which he pursued across the various political systems.