Maria Rentetzi surveys the experimental practices of radioactivity research in early-twentieth-century Vienna, focusing on radioactive materials, instruments, women's work in physics, and gendered skills. She shows how experimental cultures in radioactivity-scientific practices employed by gendered subjects who shared a certain material and epistemic style of research--were constructed and reshaped by socialist politics in Vienna at that time. She also explores the different ways experimental practices affected men and women in laboratory sciences. Rentetzi expands the notion of material culture to include not only instruments and objects but also materials that operated as both commodities and objects of scientific inquiry. She tells a multifaceted story of how purified radium ended up on laboratory benches and who extracted and isolated it from tons of residues; the individuals who designed experiments and instruments for probing radium's properties; and those who carried radium outside of the physics laboratory and into the clinic and medical amphitheatres. Rentetzi examines how the architecture of the laboratory affected men's and women's scientific work and the way in which its urban setting reflected assumptions about scientific cross-disciplinary collaborations. Following the circulation of radium and the pursuit of power through strategies of partnership and collaboration, Rentetzi redraws paths of scientific exchange and transfers the reader from scientific laboratories to hospitals and from academic to industrial sites.