Algae 4th Edition is a richly illustrated, comprehensive textbook that examines the major groups of mostly aquatic, mostly photosynthetic organisms that are informally known as algae. Following an introductory chapter, a series of chapters consider the roles of algae in biogeochemistry, algae in biotic associations, technical applications of algae, algal diversity and relationships, as well as endosymbiosis and the diversification of eukaryotic algae.

Subsequent chapters consider each of the major groups of algae in turn, with discussion of their relationships and evolutionary history, cell biology, reproduction, ecology, and diversity.

Following those chapters, three chapters cover phytoplankton ecology, marine macroalgal (seaweed) ecology, periphytic algae, and terrestrial algae.

Finally, a glossary of commonly used terms is provided as well as an extensive literature cited section, which should prove useful for both students and professionals.