This is the text of the first chapter of the new book Voice Interaction Design: Crafting the New Conversational Speech Systems by Randy Allen Harris, published by Morgan Kaufman Publishers, an imprint of Elsevier Science. "This is that rare book in Human Computer Interaction we all hope for: the presentation of a practical design process for an emerging important area that is carefully developed out of supporting science. Harris's book offers a competitive edge for designers and a provocative framing of problems for researchers in language." —Stuart Card, PARC. For the excerpt, go to http://www.acm.org/ubiquity/book/pf/v6i15_harris.pdf