L. Albert Hahn (1889-1968) was a German banker, economist, and university professor at the University of Frankfurt am Main. He was born into a family of private bankers in Frankfurt am Main on October 12, 1889. Hahn received PhDs from the University of Marburg in law in 1912 and in economics in 1919. He was on the managing board of the family bank, the Deutsche Effecten- und Wechsel-Bank, from 1919 until 1933 whilst also holding an honorary professorship at the University of Frankfurt. Clemens Matt studied economics in Graz, Nancy, Edinburgh, and Berlin and holds an MSc from the University of Edinburgh. He works for the British Government Economic Service and occupies himself with the history of economic thought in his spare time. Harald Hagemann is Professor of Economic Theory at the University of Hohenheim, Stuttgart, Germany. He is a life member of Clare Hall, University of Cambridge and is Honorary Past President of the History of Economic Thought. His main areas of research cover growth, structural change, new technologies and employment, and the history of economic analysis. His recent work also focuses on the history of modern business cycle theory and the emigration of German speaking economists after 1933.