This book is part of a two-volume work that constitutes the refereed proceedings of the 11th IFIP TC13 International Conference on Human-Computer Interaction, INTERACT 2007, held in Rio de Janeiro, Brazil in September 2007. It covers social computing, UI prototyping, user centered design methods and techniques, intelligent user interfaces, accessibility, designing for multiples devices, affective computing, 3D interaction and 3D interfaces, as well evaluation methods.