This book is different from most books on designing user interfaces since the ideas are presented as design patterns, much as you would see in Gamma's classic book on the subject had it been adapted to human-computer interfacing rather than programming. Each of the patterns and techniques presented in this book are intended to help the reader solve common design problems. Patterns and techniques are presented for web sites, desktop applications, and everything in between such as web forms, Flash, and applets. The user interface design patterns presented in this book are intended to be read by people who have some knowledge of UI design concepts and terminology: dialogs, selection, combo boxes, navigation bars, whitespace, branding, and so on. The book does not identify many widely-accepted techniques such as copy-and-paste, as it is assumed that you probably already know what this is. However, some common techniques are described here to encourage their use in other contexts -- for instance, desktop apps could make better use of Toplevel Navigation -- or to discuss them alongside alternative solutions. If you're running short on ideas, or hung up on a difficult design problem, skimming this book and its design patterns may help you produce a good solution.
Each pattern is presented with an image showing a possible implementation, a "Use When" section, a "Why" section, and a "How" section with very high level tool-independent implementation instructions. The patterns are organized into groups by function - organizing content, getting around, organizing the page, getting input from users, showing complex data, commands and action, direct manipulation, and stylistic elements.
I would highly recommend this logically structured book to anyone from programmer to graphic artist who might be involved in user interface design.