This report synthesizes findings emerging from research on mastery learning. Thirty-three documents were retrieved and analyzed for the report. The documents were concerned with mastery learning research at various levels, from elementary through postsecondary education. Specific subject areas which were the partial or total focus of the reports included: mathematics; science; reading and language arts; social studies; geography; consumer economics; history, auto mechanics; and shop. The introduction to this report offers a review of the features of mastery learning and defines mastery learning as "a strategy which seeks to raise student achievement by increasing the amount and quality of the time students spend pursuing learning activities." A discussion is included on arguments for and against the mastery teaching strategy. A general overview is presented on the effects of mastery learning on student achievement, retention, and attitudes, and recommendations for future practice are made, based on the research. (JD)