Book excerpt: The islands of the Samoan archipelago lie about 14 degrees south of the equator in the central Pacific Ocean. Politically, they are divided into two groups: Samoa (formerly Western Samoa), an indepedent state and American Samoa, a territory of the USA. The islands have been formed as a result of complex volcanic activity; they are geologically young. While many of the plants and birds of the Samoan Islands are found elsewhere in the Pacific, many of the snail species are found nowhere else on Earth. This guide is intended to permit identification of mos of the terrestrial snails, and slugs of the Samoan Islands. It is intended to be accessible to the amateur naturalist but also to provide the experienced scientist with a compact resource of information. The guide covers both the native species and the non-native, introduced species, which are generall more frequently encountered, especially at low elevations and in habits disturbed by human activities.