The Facial Action Coding System (FACS) is a comprehensive, anatomically-based system for describing all observable facial movement. It has been used for research on the psychology of emotion, to understand mental health, to detect deception, and to drive the computer generated images in special effects. This book includes original studies using FACS, the study of spontaneous behavior in both humans and animals that cuts across several fields--including Psychology, Medicine, Law, and Veterinary Medicine.