In this paper, the author reviews the research done on the learning efforts of adults and presents some high-priority directions for the future. The paper first defines major learning efforts (learning projects) and describes some recent changes in the practice and focus of adult education. It then provides a general picture of the frequency of adult participation in learning projects as well as of the duration and planning of these projects. A review then follows of several surveys which provide data on the learning efforts of adults in varied populations. These surveys are grouped according to their focus under the following categories: geographical areas, older adults, occupational categories, educational level, and peer groups. The author also summarizes a few studies that focused on motivation, the learner's planning tasks, and persons who help with the planning. The concluding section suggests eight research and development projects for the future. (EM)