This book is a result of the NATO Advanced Research Workshop on New Directions for Intelligent Tutoring Systems, held in Sintra, Portugal, October 6-10, 1990. The main idea behind the workshop was to bring together scientists with different concerns about Intelligent Tutoring Systems (ITS) in order to discuss the positive and negative aspects of the current architecture paradigm (expert module, student module, instructional module, and interface module) and, eventually, propose some modifications or radical changes to it. This was a consequence of the increasing malaise felt currently by researchers in the area of artificial intelligence and education and in particular by those concerned with ITS. One symptom of this state of affairs is the fact that people have started talking about Intelligent Learning Environ­ ments (lLE) instead of ITS. To understand the reasons for this situation we promoted the discussion of questions like: - To what extent do we need the technology of expert systems in ITS? Which other relevant AI techniques and methodologies are urgently needed? - Is ITS a tool for knowledge communication or is it rather a belief system? - How can the research already done on interactions among agents be utilized? - Is it possible to find a fonnal theory to describe and solve the current problems with ITS? The book contains the revised versions of the papers presented at the workshop. The new texts reflect the discussions that took place at the meeting.