I think relatively few people would agree with me in saying that the most important book in the field of human-computer interaction is Understanding Computers and Cognition: a New Foundation for Design, by Artificial Intelligence and language-processing expert Terry Winograd and Fernando Flores. But it is a tour-de-force. The problem that people from the usability and human-computer interaction worlds have is that early on it delves into heady concepts from neurobiology, cognitive science, ecology, perception theory, and the branch of German philosophy called phenomenology, which deals with experience and cognition. Winograd and Flores understand that cognitive science has a Cartesian and dualist hangover, and that to the extent that the theory underlying human-computer interaction relies on cognitive science, this hangover can undermine user-centered design. Cognitve science understands people as robots, but real people are embodied, and often emotional, irrational, idosyncratic, biased, and can respond to systems in ways that designers and engineers may find baffling.