What could it mean to be a physicist specialized in radioactivity in the early 20th century Vienna? More specifically, what could it mean to be a woman experimenter in radioactivity during that time? This dissertation focuses on the lived experiences of the women experimenters of the <i>Institut für Radiumforschung</i> in Vienna between 1910 and 1938. As one of three leading European Institutes specializing in radioactivity, the Institute had a very strong staff. At a time when there were few women in physics, one third of the Institute's researchers were women. Furthermore, they were not just technicians but were independent researchers who published at about the same rate as their male colleagues. This study accounts for the exceptional constellation of factors that contributed to the unique position of women in Vienna as active experimenters. Three main threads structure this study. One is the role of the civic culture of Vienna and the spatial arrangements specific to the <i>Mediziner-Viertel</i> in establishing the context of the intellectual work of the physicists. A second concerns the ways the Institute's architecture helped to define the scientific activity in its laboratories and to establish the gendered identities of the physicists it housed. The third examines how the social conditions of the Institute influenced the deployment of instrumentation and experimental procedures especially during the Cambridge-Vienna controversy of the 1920s. These threads are unified by their relation to the changing political context during the three contrasting periods in which the story unfolds: a) from the end of the 19th century to the end of the First World War, when new movements, including feminism, Social Democracy, and Christian Socialism, shaped the Viennese political scene, b) the period of Red Vienna, 1919 to 1934, when Social Democrats had control of the City of Vienna, and c) the period from 1934 to the <i>Anschluss</i> in 1938, during which fascists and Nazis seized power in Austria. As I show, the careers of the Institute's women were shaped in good part by the shifting meanings, and the politics, that attached to being a "woman experimenter" in Vienna from 1910 to the beginning of the Second World War. / Ph. D.