This Book excerpts chapters from "Freshwater Mollusks of the World - A Distribution Atlas," edited by Charles Lydeard and Kevin S. Cummings, published by Johns Hopkins University Press. The atlas systematically covers various families of freshwater mollusks, including gastropods and bivalves, providing taxonomic information, distribution details, and insights into their biology and evolution. Chapters are authored by different experts and often focus on specific families like Viviparidae, Thiaridae, and Unionidae, discussing their classification, diversity, and biogeography. The work also addresses conservation concerns and the impact of invasive species on these aquatic ecosystems.