Diatoms are microscopic algae that are found throughout the world in aquatic environments. They are the focus of many scientific endeavors because they play an important role in geochemical cycling and biologic communities; they are indicator organisms due to their sensitivity to environmental changes; and their silica frustule preserves well in the sediment providing a fossil record for examining environmental change. Scientific studies involving diatom identification benefit from accessible, reference materials of diatom taxa, including regional and comprehensive diatom floras. The "Stuart R. Stidolph Diatom Atlas" is a digital atlas of light microscopy images taken of diatom flora from coastal regions throughout the world. The atlas will be an essential reference on coastal diatoms, and will be of interest to aquatic biologists, coastal ecologists, oceanographers, and geologists from all over the globe.