An introductory guide and key to freshwater bryozoa of Britain and Europe. Bryozoa is divided into three classes of which Stenolaemata is marine and not considered. This guide covers freshwater members of the classes Gymnolaemata (which contains both freshwater and marine species) and Phylactolaemata (which is entirely confined to freshwater). The British and European Phylactolaemata comprise four families, while Gymnolaemata contains one order with two genera under it. An illustrated identification key is followed by a short section with notes on species that are intended to help confirm identification and provide additional information. Little is known of the relative abundance of species, and this aspect is mentioned only when a species is notably rare or common.