About the author Nils J. Nilsson's long and rich research career has contributed much to Al. His previous books, considered classics in the field, include Learning Machines, Problem-Solving Methods in Artificial Intelligence, Logical Foundations of Artificial Intelligence, and Principles of Artificial Intelligence. Dr. Nilsson is Kumagai Professor of Engineering, Emeritus, at Stanford University. He has served on the editorial boards of Artificial Intelligence and Machine Learning and as an area editor for the Joumal of the Association for Computing Machinery. Former chairman of the Department of Computer Science at Stanford and Former Director of the SRl Artificial Intelligence Center, he is also a past president and fellow of the American Association for Artificial Intelligence.