Spiethoff considered one of the founders of modern economic research in economies. As his Bulgarian colleague Albert Aftalion Spiethoff had one of the first points to the accelerator principle. After studying economics at the Friedrich-Wilhelms-University of Berlin where he was assistant to 1908 by Gustav von Schmoller, one of the most important representatives of the so-called younger Historical School of Economics. During his Assitentenzeit his doctorate on 18 February 1905 with a dissertation on "Contributions to the theory and analysis of the general economic crisis." 1907 and his habilitation. Following this, he became a full professor at the German-speaking Karl-Ferdinand University in Prague, one of the leading universities in Central Europe at that time. After World War II, he was appointed to a professorship at the University of Bonn, where he retired in the 1939th.