The purpose of this article is to explore the inner workings of a PhD thesis that analyzes the careers of women physical education teachers in France in the second half of the twentieth century. This contribution, which is epistemological, methodological, and reflective in nature, examines three aspects: the genesis of the research project, the search for archives, and the treatment of the sources. This history of women PE teachers, whose author is both a member of the community he studied and an outside observer specializing in the field of gender relations, begins by raising the question of what is identical and different. The article goes on to scrutinize the sources chosen, as well as the material, technical, and social aspects of the research. Lastly, this article focuses on ways of interpreting sources through the prism of physical and emotional experiences which a historian may undergo as he explores the archives.