Preface These are exciting and challenging times for education.The demands of a global society have changed the requirements for educated people; we now need to learn new skills continuously during our lifetimes, analyze quickly, make clear judgments, and exercise great creativity. We need to work both independently and in collaboration and to create engaging learning communities. Yet the current educational establish- ment is not up to these challenge; students work in isolation on repetitive assign- ments, in classes and schedules fixed in place and time. Technologic and scientific innovations promise to dramatically enhance exiting learning methods. This book describes the use of artificial intelligence in education , a young field that explores theories about learning and builds software that delivers differential teaching, systems that adapt their teaching response after reasoning about student needs and domain knowledge. These systems support people who work alone or in collaborative inquiry. They support students to question their own knowledge, and to rapidly access and integrate global information. This book describes how to build these tutors and how to produce the best possible learning environment, whether for classroom instruction or lifelong learning. I had two goals in writing this book. The first was to provide a readable introduc- tion and sound foundation to the discipline so people can extract theoretical and practical knowledge from the large body of scientific journals, proceedings, and con-