This book contains revised versions of the papers presented at the NATO Advanced Research Workshop "New Directions for Intelligent Tutoring Systems"held in Sintra, Portugal, October 6-10, 1991. The aim of the workshop was to bring together scientists working on Intelligent Tutoring Systems (ITS) in order to discuss positive and negative aspects of the current architecture paradigm (expert module, student module, instructional module, and and interface module) and to propose changes. The book is divided into five parts: Foundations, Student Modelling, ITS Principles and Practice, Belief Systems, and Interaction Among Agents). Each part is organized around a major theme which is observed from different points of view. Some papers have a formal or theoretical orientation, some discuss applications and implementations, and some combine both aspects. The book will be useful for all researchers involved in the application of artificial intelligence to education.