We report on studies in Tanzania, Kenya, Uganda and South Africa over the past 22 years that have yielded estimates of land-snail diversity in the main forest types occurring in East and eastern southern Africa. When supplemented with the results of similar research in Madagascar and West Africa by other workers, the information provides a more detailed picture of the patterns of land-snail diversity on the continent than was available to Solem (1984). We describe our field methods, re-examine Solem’s (1984) assessments of sympatric, allopatric and mosaic diversity patterns in African forests and provide a review of overall species number at continental, regional and country-wide scales, and in the main African forest biomes that have been studied.