Nearly 200 years ago, a naturalist named Rafinesque stood on the banks of the Ohio River and began to describe the freshwater mussels he found there. Since that time these animals have become the most imperiled animals in North America. Dozens of species have become extinct, and it is estimated that two-thirds of the remaining freshwater mussels face a similar fate. Yet, despite their importance, the mussels of Ohio remain a poorly documented and largely mysterious fauna. The Freshwater Mussels of Ohio by G. Thomas Watters, Michael A. Hoggarth, and David H. Stansbery brings together, for the first time, the most up-to-date research on Ohio’s mussels. Designed for the weekend naturalist and scientist alike, it synthesizes recent work on genetics, biology, and systematics into one book. Each species is illustrated to a degree not found in any other work. Full-page color plates depict shell variation, hinge detail, and beak sculpture. Full-page maps show the distribution of each species based upon the collections of numerous museums (with historical distributions dating from the 1800s). In addition to species accounts, the book has a substantive introduction that includes information on basic biology, human use, and conservation issues. Extensive synonymies, a key to all species, and an illustrated glossary are included as well.