Nuclear physics between 1921 and 1947 shaped more than any other science thepolitical landscape of our century and the public opinion on physical research. Using quantitative scientometric methods, a new branch in the history of science, the author focuses on the developments of nuclear physics in these formative years paying special attention to theimpact of German emigrants on the evolution of the field as a cognitive and social unity. The book is based on a thorough analysis of various citation analyses thus producing results that should be more replicable and more objective. The scientometric techniques should complement the more qualitative approach usually applied in historical writing.