This bulletin focuses on cooperative learning with an emphasis on its use in science classrooms. A comprehensive review of the educational literature on cooperative learning is presented. Major sections of this document include the following: (1) why cooperative learning in science? (2) some characteristics of cooperative learning; (3) some varieties of cooperative learning; (4) research on cooperative learning; (5) cooperative learning in science classrooms; (6) some questions and controversies related to cooperative learning; (7) cooperative learning: benefits revisited; and (8) staff development and cooperative learning. (PR)