Mécanisme de la Physionomie Humaine was a rare book when it was published in Paris in 1862. Few copies were produced, as the text was accompanied by about 100 original photographic prints, each of which had to be pasted into the Album. The fascicule containing the Introduction appeared first, followed by the Scientific Section, and then an Aesthetic Section was published some months later. This sequential publication had the advantage that criticisms made by reviewers of, for example, the Scientific Section, were answered by Duchenne in the subsequent Aesthetic Section! Together, the three fascicules constituted the “Text” of Mécanisme de la Physionomie Humaine. They were either sold bound together or could be bought loose and bound by purchasers in their own preferred style.

Although important in the development of modern experimental psychology and physiology, original copies of this book have been restricted to a few major libraries. Our aim in producing this book was to make Duchenne's text and photographs more widely available for the first time. Mécanisme de la Physionomie Humaine is historically important as the first series of published physiological experiments to be illustrated by photography; it also has relevance to modern psychology, neurology, plastic surgery, and the study of fine arts, which is reflected in the four accompanying commentary chapters.