The Utah Mollusk Identification Guide offers up-to-date information for identifying aquatic and terrestrial snails, slugs, clams, and mussels within the state of Utah, providing comparative tables, taxonomic keys, and more than 230 images, including many type specimen images published for the first time. Amateur naturalists and biologists alike will benefit from detailed information regarding size, type, specimen location, junior synonyms (including taxonomy notes), original descriptions for each of the 139 species, and comments to help differentiate similar species. In contrast to older guides, this book includes data on the external and internal anatomy of mollusks. Taxonomic names are updated to incorporate the latest information available. Family descriptions and miscellaneous data on ecology, life history, and genetics are also presented. Distribution data are based on historical articles, museum records, personal observations, and collections. Although the focus is on Utah mollusks, many species are widely distributed and the data, images, references, and taxonomy details within the guide will be of interest to many outside the state.