Bristle worms, or oligochaetes, are a large and diverse group of invertebrates. Most oligochaetes living in this region live in fresh or brackish water: no fewer than 136 species in total. They play an important ecological role thereby giving much information about the condition of the ecosystem. This important, bulky book is the first reference work on the freshwater and brackish water polychaetes in the Netherlands, Belgium and Germany. It offers a wealth of ecological and taxonomic background information. Includes a new user determination key. The key is based on characteristics that are relatively easy to distinguish, without specialized equipment. - a comprehensive overview on morphology, collecting and preservation, identification and ecology - 136 species including the oligochaete fauna of Germany - a new, practical key for the identification based on characteristics that are relatively easy to distinguish  - many photographs and schematic drawings - backgroundinformation on ecology and distribution - A unique tool for aquatic ecologists and water quality management. Summary in Dutch: Het eerste naslagwerk over de zoet- en brakwaterborstelwormen van Nederland en België. Biedt een schat aan ecologische en taxonomische achtergrondinformatie en bevat een nieuwe, gebruiksvriendelijke determinatiesleutel. Met meer dan 300 foto's en illustraties. Onmisbaar voor aquatisch ecologen en waterkwaliteitsbeheerders. Trefwoorden: macrofauna, aquatische wormen, soorten, oligochaeten, borstelwormen, determineren, taxonomie, determinatie, zoet water, brak water, waterkwaliteitsbeheer, aquatische ecologie, hydrobiologie, water quality management, aquatic ecology, hydrobiology, bristleworms, bristle worms, Oligochaetes, Nederland, Belgie