The present volume contains a large number of the papers contributed to the Advanced Study Institute on the Psychological and Educational Foundations of Technology-Based Learning Environments, which took place in Crete in the summer of 1992. The purpose of the Advanced Study Institute was to bring together a small number of senior lecturers and advanced graduate students to investigate and discuss the psychological and educational foundations of technology-based learning environments and to draw the implications of recent research findings in the area of cognitive science for the development of educational technology. As is apparent from the diverse nature of the contributions included in this volume, the participants at the ASI came from different backgrounds and looked at the construction of technology -based learning environments from rather diverse points of view. Despite the diversity, a surprising degree of overlap and agreement was achieved. Most of the contributors agreed that the kinds of technology-supported learning environments we should construct should stimulate students to be active and constructive in their knowledge-building efforts, embed learning in meaningful and authentic activities, encourage collaboration and social interaction, and take into consideration students' prior knowledge and beliefs.