This book represents a collection of the classic and contemporary readings in the field of Intelligent User Interfaces. An invaluable resource for students, professors, research scientists and engineers, it includes both fundamental research and applied innovations in the key areas of IUI including input analysis, output generation, user and discourse adapted interaction, agent-based interaction, model-based interface design, and evaluation. Editors Maybury and Wahlster, two prominent researchers in the field of Intelligent User Interfaces, offer an introduction to the field along with commentary on each topic. In order to provide a uniquely synergistic view they chose a five person interdisciplinary review board to act as a sounding board for the organization of the book that included paper selection and reviewing commentary for the editors. Each paper concludes with a reflection by the original author on what worked, what did not, and where opportunities remain, as well as commentary on subsequent research and advances since the publication of their work, including important developments and key follow-up publications by the author and others. Editorial Review Board: Dr. Oliviero Stock, Instituto per la Ricerca Scientifica e Tecnologica (IRST), Trento, Italy Dr. Eduard Hovy, Information Science Institute (ISI), University of Southern California Dr. Johanna D. Moore, University of Pittsburgh Dr. Steven F. Roth, Robotics Institute, Carnegie Mellon University Dr. Sharon Oviatt, Oregon Graduate Institute of Science and Technology