This article discusses how the German and the international academic debates about corporate finance developed in the course of the past 50 years, and how they are related. Four different phases of development are distinguished and contrasted. The main aspect in which they differ relates to the assumption of whether the capital market is perfect or not. This assumption shapes the main propositions of the theory of corporate finance but also, in a more general sense, determines which topics in finance attract the attention of researchers and therefore are a topic of the theory. During the first two phases of development, one can still see specific German features of the academic discourse, whereas in the latter two phases, German authors have become more and more part of one single international research community.