Extensive scientific study of bats suggests that they are long-lived, slowly reproducing animals adapted to relatively stable environments. As such they might be expected to exist in communities heavily influenced by biotic interactions. This book begins with an overview of bat biology, including their systematic diversity and methodological problems in bat research. This is followed by examples of local bat community surveys from the major biogeographic regions. The evidence bearing upon resource limitation and competition in bats is reviewed. Then patterns in species richness, taxonomic, packing, biomass, numerical density, trophic and morphological diversity are described. The relevance of these to the nature of bat communities is examined. Major habitats and their histories are shown to be powerful predictors of important aspects of bat community structure.