Current research and evaluation studies describe changing knowledge about the effects and conditions of computer-based tools in learning and teaching in elementary and secondary school classrooms. Current studies of computer-based tool use are characterized by: (1) a focus on many dimensions of learning, learners, and learning environments; (2) an increasing concern for learners' individual needs; (3) an interest in the process as well as the outcomes; (4) a concern for the effects of knowledge representation on learning and understanding; (5) interest in teachers' roles; (6) a focus on collaborative learning; and (7) a concern for evaluation methods. While tools are most often used to support the writing process, other applications include social studies problem solving; mathematics concept formation and problem solving; modelling of physical, biological, and social systems; graphing; science collaboration through the use of networking tools; and databases to support scientific inquiry. Recommended areas for research and development include learning and teaching using computer-based tools, reassessment to facilitate the integration of tools into the curriculum, evaluation methods, teacher preparation and enhancement, the development and application of new technologies, and social issues. (90 references) (GL)