The system described in the book is impressive as one of a small number of complete and working spoken natural language dialogue systems that have been developed . . . . Many of the techniques in the book are interesting and well thought out, and should prompt useful discussion and further work. I would therefore recommend it to those working in computational linguistics who are concerned with practical issues, as a book to be read seriously but critically. --The Computer Journal It is nice to see these ideas put together and made to work for the teaching task. --User Modeling and User-Adapted Interaction The book is well organized, with useful figures and appendices, a good index and comprehensive references. ... The book offers a wonderful model for the presentation of a complex AI project. -- Computing Reviews