An emerging group of marketing experts strove to manage the apparent contradictions of interwar German capitalism with consumer markets that seemed increasingly rationalized yet at the same time highly volatile and emotional. This chapter explores the professional and intellectual debates surrounding consumer capitalism during the 1920s and early 1930s. I ask about the professional perceptions especially among market researchers as well as among product designers and graphic artists. In trade journals and professional publications of the era, we find contradictory analyses of the nature of consumer markets and divergent opinions over what type of expert was best suited to managing them – engineers, psychologists, or even artists? Whereas interwar designers frequently stressed the importance of functionality and standardization, market researchers emphasized the emotional side of modern consumption. They all shared, however, a common belief in the growing importance of consumers as actors in interwar capitalism.