Yorick Wilks is a Professor of Computer Science at the University of Sheffield, where he directs the Institute for Language, Speech and Hearing. He received his M. A. and Ph.D. (1968) from Pembroke College, Cambridge. He has also taught or researched at Stanford, Edinburgh, Geneva, Essex and New Mexico State Universities. His interests are artificial intelligence and the computer processing of language, knowledge and belief, and his recent books include: Artificial Believers (Erlbaum 1991), Electric Words (MIT, 1996) and Machine Conversations (Kluwer, 2001). He is a Fellow of the European and American Societies for Artificial Intelligence, a Fellow of of the EPSRC College of Computing and a member of the UK Computing Research Council.