Affective computing is a fascinating new area of research emerging in computer science. It dwells on problems where "computing is related to, arises from or deliberately influences emotions" (Picard 1997). Following this new research direction and considering the human element as crucial in designing and implementing interactive intelligent interfaces, affective computing is now influencing the way we shape, design, construct, and evaluate human-computer interaction and computer-mediated communcation. This book originates from a workshop devoted to affective interactions. It presents revised full versions of several papers accepted in preliminary version for the workshop and various selectively solicited papers by key people as well as an introductory survey by the volume editor and interview with Rosaling Picard, a pioneer researcher in the field. The book competently assesses the state of the art in this fascinating new field.