F-M PainFACS 4.0 is a pioneer and revolutionary creation of the most powerful and consensual instrument to scientifically measure and understand emotion in the human face, defends Dr. Freitas-Magalhães, Ph.D., the world's leading expert for Neuroscience and Biobehavioral Psychology and the Encyclopedia of Human Behavior, by Elsevier, Oxford, in his pioneering and extraordinary book.