These biological bibliographies may be found useful as pertinent references for those working in water pollution control, sewage treatment, and water treatment. The selected biological references applicable to water pollution control programs might be most effectively applied if a general understanding of ecology is gained. The selected biological references applicable to sewage and industrial waste treatment, in general, include publications that deal directly with specific organisms, rather than those that are of a chemical-biological nature. The selected biological references applicable to water treatment are organized into bibliographies that will refer the reader to organism problems that have been associated with specific steps in the water treatment process.