The plants and plantlike organisms informally grouped together as algae show great diversity of form and size and occur in a wide variety of habitats. These extremely important photosynthesizers are also economically significant. For example, some species contaminate water supplies; others provide food for aquatic animals and for man; still others yield agar, diatomaceous earth, or fertilizer. This guide to the literature on algae is not intended to be a comprehensive bibliography, but is designed to provide the reader with a set of resources that can be used to focus on the topics. The document lists the subject headings used by the Library of Congress in cataloging information on algae. It also contains citations of materials categorized as: (1) introductions to the topic; (2) general surveys; (3) additional titles; (4) handbooks; (5) bibliographies; (6) reviews and conference proceedings; (7) government publications; (8) abstracting and indexing services; (9) journals; (10) representative journal articles; (11) technical reports; and (12) selected materials. (CW)