This chapter reviews the use of the environmental scanning electron microscope (ESEM) as a general research and experimental tool in the study and conservation of cultural property. As such, it departs from a typical survey of the literature and instead concentrates on the practical development and application of the ESEM system - based chiefly on personal experience in the allied fields of Museum and Conservation Science. These are both multidisciplinary fields, applying information from chemistry, materials science, art history and other areas to problems such as material degradation mechanisms, the testing of new preservation techniques and the study of ancient materials and technologies.