The Apple Classrooms of Tomorrow (ACOT) research project provides classroom sites with equipment, ongoing support, and training, enabling educators to discover the potential of networked learning environments. ACOT networks link together technology from Apple IIe computers and Image Writer printers, to Macintosh II systems, synthesizers, laserdisc players, scanners, and LaserWriter printers. Curriculums include subjects from reading, writing, and arithmetic to trigonometry, and networked software ranges from drill and practice to word processing and curriculum management tools. Teaching approaches that utilize the network span from directing students to work through electronic workbooks, to coaching them as they create entire curriculum units. Three kinds of network-supported learning environments can be utilized: self-paced, project-based, and knowledge-building. The first two reflect the current activity of ACOT classrooms, while the third predicts future ACOT activities. Two current research and development projects are described which demonstrate the use and value of electronic networks for building knowledge in a collaborative environment. (GL)