Land snails are considered one of the best-explored invertebrates of temperate and boreal zones. With respect to the extensive knowledge about their ecology and distribution, land snails make a great model group for studying various topics. Snails contributed to our knowledge about the nestedness of assemblage composition, differences in biology and distribution of large and small species (regarding their ability for passive dispersal), Quaternary landscape evolution, and the latitudinal diversity gradient. Other topics still remain open, such as the effects of predation and interspecific competition among land-snail assemblages and the association of some species to generally unfavourable conditions (e.g. areas of extremely cold temperatures or calcium-poor sites).