Book excerpt: Using extensive practical examples, the Practitioner's Handbook for User Interface Design and Development illuminates today's best practices for user interface design, usability, and user-centered development. Robert J. Torres introduces user interfaces from three points of view: the user, the developer, and the system. Next, he introduces a complete user-centered UI development process, beginning at the highest level and then drilling down to each phase of the lifecycle. For every stage, Torres offers clear principles, specific guidelines, and practical heuristics for self-assessment.