This dissertation examines the career and methodological thinking of the sociologist Paul F. Lazarsfeld (1901-1976) from interwar Vienna to the mid-twentieth century United States. It locates the roots of the research system and graduate student training at the Columbia University Bureau of Applied Social Research in his Vienna formation. Lazarsfeld’s approach to social research mediated between extreme Central European positions on the relationship between the natural sciences and the humanities and social sciences. Examination of Lazarsfeld’s Viennese milieu uncovers the specific ways of thinking through this problem and the particular meanings attached to them that were highly local but embedded in conversations and scientific practices throughout Central Europe and across the Atlantic. In his American years, new constellations of thinkers and new political contexts imbued the problem with new meanings. A contextualized reconstruction of Lazarsfeld’s career contributes to the ongoing revision of our understanding of “posivitism.” Lazarsfeld anticipated “post-positivist” perspectives on skill, training, and objectivity that animate the practical turn in the history of science but from within the tradition of Viennese positivism. The dissertation is divided into three parts in rough chronological order but focused around Vienna from the end of the First World War until the early 1930s and the United States from the mid-1940s to the early 1960s. These periods cover Lazarsfeld’s young adulthood in Vienna and the height of his influence and activity at Columbia University in postwar America respectively. Ways of doing social science that have seemed particularly “American” appear less indigenous because they can be traced in part back to Austria through Lazarsfeld. Attention to Lazarsfeld’s idiosyncratic approach makes the supposed methodological consensus of the postwar American social sciences that vaunted “basic” or “pure” science and a “natural science model” appear less uniform. These findings open up space for nuanced examination of the relationships between methodology and context.