"Mecanisme de la Physionomie Humaine" by nineteenth-century French neurologist Duchenne de Boulogne explores the portrayal of emotions through facial expressions, using photography and electrical muscle stimulation. This groundbreaking work, published in 1862, was revolutionary in psychology and physiology, marking the first use of photography to document and validate scientific experiments. The book includes over 100 original photographic prints, providing a detailed study of facial anatomy and emotion depiction. Despite its significance, Duchenne's contribution has been underrecognized, with limited copies available in a few libraries across the United States and Europe.
