Why do we bite people we feel affection towards? Why do dogs wag their tails? Or cats purr? Why do we get embarrassed, and why does embarrassment make us blush? These, and many other questions about the emotional life of man and animals are answered in this remarkable book. The Expression of the Emotions in Man and Animals was an immediate best-seller when it was first published in 1872 and still provides the point of departure for research into emotion and facial expression. In his study of infants and children (including a delightfully objective study of his own baby's smiles and pouts), of the insane, of painting and sculpture, of cats and dogs and monkeys, and of the ways that people in different cultures express their feelings, Darwin's insights have not been improved upon by modern science. This definitive edition contains a substantial new Introduction and Afterword by Paul Ekman. Ekman also provides commentaries that use the latest scientific knowledge to elaborate, support and occasionally challenge Darwin's insights.