The discovery of light-sensitive chemicals in mid-19th-century Europe carried large implications - for scientists, technicians, astronomers and for the businesspeople who soon made family portraiture standard tabletop fare in middle-class homes. In this work, the authors begin with a history of the process itself. Tracing the daguerreotype's origins and development, they proceed to discuss what researchers in the 20th century discovered about the chemistry of the daguerreotype. They also address practical curatorial issues, describing how to restore and preserve the artefacts themselves.