Computers are increasingly able to mimic abilities we often think of as exclusively human. Humans, Computers and Wizards considers current perspectives on human-computer interaction and argues for the value of an approach taken from sociology which is based on conversation analysis. Using data taken from a major, European Union funded project on speech understanding, the SunDial project, this book shows how this data may be analyzed to yield important conclusions about the organisation of both human-human and human-computer information dialogues. It describes the Wizard-of-Oz method of collecting speech dialogues from people who believe they are interacting with a speech understanding system before that system has been fully designed or built and it shows how the resulting dialogues may be analyzed to guide further design