Asbestos causes three major diseases, asbestosis, lung cancer and mesothelioma. Originally a coveted curiosity, asbestos became the ideal material for an industrialising world. It enhanced the durability and safety of high-speed machines and engines, electrical products and the buildings which contained them. While asbestos use increased in the early twentieth century, numbers of occupation-related injuries in the West began to fall. Deaths from industrial cancers and chemical poisonings, however, overtook traditional hazards such as lead poisoning. From the 1930s studies began to point to the dangers of asbestos. By 1953 it was listed as a carcinogen in the UK. The link between asbestos and mesothelioma, a once-rare and aggressive cancer, was made by South-African-born pathologist Chris Wagner. His research stimulated other international studies in the 1960s and 1970s, including that of Peter Elmes in Belfast. These pages are based on bequests of Wagner’s and Elmes’s research materials to the Science Museum. Together they chart a significant transformation in perceptions of what was once popularly described as the ‘magic mineral’.