This article investigates the status assigned to Max Weber’s The Protestant Ethic and the Spirit of Capitalism as a case study on the development of the concept of theory in twentieth century sociology. I trace this development in the interplay between scholars in the United States and Germany and distinguish three waves of meaning given to the text. The transitions between these phases were brought about by an initial process of mystification of the text in the 1930s and a dynamic (...) of de- and re-mystification beginning in the 1980s. Following this process of (re)interpretation over time, I show that at the beginning of the century the work was perceived as an empirical inquiry, while at the end of the century it was treated as pure theory. Based on the example of the peculiarities of the Weberian expert communities in the United States and Germany, I analyze how the invention of a concept of theory as independent from empirical evidence helped to stabilize the value of scholarly expertise on Weber in the face of otherwise declining resonance of the text. The analysis of this paradigmatic case adds to our understanding of the development, uses, and meaning of theory in contemporary sociology. (shrink)