With more than 29,000 species, fishes are the most diverse group of vertebrates on the planet. Of that number, more than 12,000 species are found in freshwater ecosystems, which occupy less than 1 percent of the Earth's surface and contain only 2.4 percent of plant and animal species. But, on a hectare-for-hectare basis, freshwater ecosystems are richer in species than more extensive terrestrial and marine habitats. Examination of the distribution patterns of fishes in these fresh waters reveals much about continental movements and climate changes and has long been critical to biogeographical studies and research in ecology and evolution. Tim M. Berra's seminal resource, "Freshwater Fish Distribution", maps the 169 fish families that swim in fresh water around the world. Each family account includes the class, subclass, and order; a pronunciation guide to the family name; life cycle information; and interesting natural history facts. Each account is illustrated, many with historical nineteenth-century woodcuts. Now available in paperback, this heavily cited work in ichthyology and biogeography will serve as a reference for students, a research support for professors, and a helpful guide for tropical fish hobbyists and anglers.