Provides an essential source for user interface design rules and how, when, and why to apply them Arms designers with the science behind each design rule, allowing them to make informed decisions in projects, and to explain those decisions to others Equips readers with the knowledge to make educated tradeoffs between competing rules, project deadlines, and budget pressures Completely updated and revised, including additional coverage in such areas as persuasion, cognitive economics and decision making, emotions, trust, habit formation, and speech UIs