The definitive resource on the biology and evolution of freshwater mollusks. There are more species of freshwater mollusks―well over 5,000―than all the mammal species of the world. Freshwater mollusks are also arguably the most endangered fauna on the planet. Yet few references exist for researchers, shell enthusiasts, and general readers who are interested in learning more about these fascinating creatures. In Freshwater Mollusks of the World, Charles Lydeard and Kevin S. Cummings fill that void with contributions from dozens of renowned mollusk experts. Touching on 34 families of freshwater gastropods (snails) and 9 families of freshwater bivalves (mussels and clams), each chapter provides a synthesis of the latest research on the diversity and evolutionary relationships of the family. The book also includes • a look at how evolving DNA sequencing data techniques help shed light on mollusk taxonomy • distribution maps of each family's biogeographic locales • a representative photo and distribution map for each of the freshwater mollusk families • the latest information on each family's conservation status―and how to reverse the habitat destruction, modification, and pollution that threatens it • a discussion of the ecological and economic damages caused by invasive mollusk species, as well as their role as disease vectors Mollusks provide us with amazing biogeographical insights: their ancient fossil record goes back over 500 million years, and their distribution patterns are a reflection of past continental and climate changes. The only comprehensive summary of systematic and biodiversity information on freshwater mollusk families throughout the world, this reference is a must for malacologists, limnologists, ichthyologists, stream ecologists, biogeographers, and conservation biologists.