This CD is an atlas of images of minerals as seen in thin section using a polarizing microscope. Minerals are listed according to structure and composition using a sequence following the Dana system. There is also an alphabetical index. From either of these lists, the user can access any page in the atlas by clicking on the mineral or topic name. The first section deals with seven fundamental optical properties, followed by sixty-five minerals and images of alteration textures. Each page includes the mineral name, chemical formula, two to four images, and explanatory text. All images can be enlarged to near-screen size. An Atlas of Minerals in Thin Section is an ideal supplement for undergraduate laboratory courses in optical mineralogy, petrology, and earth materials.