This volume presents high quality, state-of-the-art research ideas and results from theoretic, algorithmic and application viewpoints. It contains contributions by leading experts in the obsequious scientific and technological field of multimedia. The volume was developed from a four-year collaboration among research groups participating in the European network of Excellence on Multimedia Understanding, Semantics, Computation and learning (MUSCLE). The book specifically focuses on interaction with multimedia content with special emphasis on multimodal interfaces for accessing multimedia information. Designed for a professional audience composed of practitioners and researchers in industry, the book is also suitable for advanced-level students in computer science.