The authors present the first detailed description of the freshwater centric, araphid and eunotioid diatoms of coastal ecosystems of the Laurentian Great Lakes. 49 plates with hundreds of light micrographs of diatom taxa, from 28 genera, recorded in 207 samples from 106 wetlands, embayments, high energy and deep, nearshore locales of the Great Lakes are presented. Descriptions and illustrations of the taxa encountered, as well as autecological information are presented to round up the content of this volume. In addition to taxonomic information, these data are intended to assist future biomonitoring and paleolimnological efforts. This volume is of interest to scientists working on diatoms, particularly those interested in diatoms from the Great Lakes area. It will help in the study of hydrological changes, eutrophication, the effects of invasive species, climate change and pollutant impacts not only in the Laurentian Great Lakes but in most freshwater habitats.