This volume brings together scholars from different disciplinary backgrounds to discuss how women contributed to the making, pedagogy, institutionalisation and communication of scientific knowledge in the twentieth century, and to reflect on the theoretical and methodological challenges of documenting such hidden contributions. Featuring examples from China, former Czechoslovakia, Greece, Hungary, India, Japan, Romania, the United Kingdom and the United States, the contributors discuss women's engagement with science across different institutional and non-institutional sites, ranging from the laboratory and the school to the clinic, the home and the media. The volume moves beyond the professional scientist model to enlarge our understanding of women's participation in twentieth-century science and document the complex combination of factors that rendered such contributions (in)visible to contemporaries and future generations.