 In the 1970s, Rohwer researched the history of cryptanalysis in World War II and especially the decoding of Enigma by the British and Polish scientists.In a cooperation of the Bibliothek für Zeitgeschichte and the University of Stuttgart, the congress "Der Mord an den europäischen Juden" (The murder of the European Jews) took place in May 1984.Together with Eberhard Jäckel, Rohwer edited the book "Der Mord an den Juden im Zweiten Weltkrieg.