Every smile is the product of physical processes common to all humans. But since the dawn of civilization, the upward movement of the muscles of the face has carried a bewildering range of meanings. Supreme enlightenment is reflected in the holy smile of the Buddha, yet the Victorians thought of open-mouthed smiling as obscene, and nineteenth-century English and American slang equated "smiling" with drinking whisky.In A Brief History of the Smile,...