In this highly readable study, one of the great pioneers of modern science examines how people and animals display varieties of emotions via their facial expressions. British naturalist Charles Darwin—who expounded the theory of evolution by natural selection, the principle that launched a scientific revolution—based this survey on his personal observations. Most of his findings were proven by later research, and today's behavioral scientists continue to draw upon this work for both knowledge and inspiration.

A bestseller when it was first published in 1872, Darwin's inquiry addresses issues related to human origins and psychology in terms of evolutionary values. His methods include the study of facial expressions in infants and children, the insane, animals, painting and sculpture, and among people in different cultures. Also notable is the fact that this is one of the first books to employ photographs in the interests of science. Abounding in anecdotes and literary quotations, the work offers a direct approach that makes it accessible to professionals and amateurs alike—in fact, to anyone with an inquiring mind.