Herman Diederiks was an academic entrepreneur. Many of today's scholarly networks in the field of crime and justice history ultimately date back to his pioneer efforts. His interests even ranged more broadly, extending to demographic and oral history among other things. Herman joined the department of economic and social history of the University of Leiden around 1970, at a time when it was common in Dutch academia to hire people for teaching who would complete their PhD later. He soon became secretary of the history section of the national Academic Council. In 1973, together with Sjoerd Faber, Herman founded the Dutch Group for the Study of Penal History - an informal and diverse group of scholars and PhD-students who regularly met in order to discuss each other's work. In subsequent years interest in the history of crime and justice was growing in several countries. In 1977 Herman and the Dutch Group organized the very first international conference, held in Amsterdam and Leiden, devoted exclusively to this subject. The next year, under the aegis of the Maison des Sciences de l'Homme, Paris, Herman, together with Maurice Aymard and Pieter Spierenburg, founded the International Association for the History of Crime and Criminal Justice.
In 1982 Herman defended his dissertation at the University of Amsterdam. It was published as Een stad in verval: Amsterdam omstreeks 1800, demografisch, economisch, ruimtelĳk (Meppel: Boom). This quantitative urban study was characteristic for his scholarly approach: he chose to focus, not on Amsterdam's greatness, but on a period of inglorious decline, realizing that such a focus can yield useful insights. With articles on aspects of crime and justice history, in Dutch as well as English, Herman also contributed to collective volumes and journals. In 1992 he published In een land van justitie: Criminaliteit van vrouwen, soldaten en ambtenaren in de 18e-eeuwse Republiek (Hilversum: Verloren) (In a land of justice: Criminality of women, soldiers and civil servants in the eighteenth-century Dutch Republic).
His major efforts continued to be directed at establishing scholarly contacts all over the world. Already by the early 1980s he got the nickname The Flying Dutchman. Throughout the 1980s and the first half of the 1990s he was the inspiring force behind several international conferences in crime and justice history as well as annual colloquia in the Maison des Sciences de l'Homme. He was also quite a sportsman. During a bike ride in the Ardèche in August 1995 he fell from a bridge; it did not seem that serious and he needed a minor operation, but it turned out that he had a weak spot in his aorta which led to his death.
Pieter C. Spierenburg