The Expression of the Emotions in Man and Animals is Charles Darwin's third major work of evolutionary theory, following On the Origin of Species (1859) and The Descent of Man (1871). Initially intended as a chapter in The Descent of Man, The Expression grew in length and was published separately in 1872. This book concerns the biological aspects of emotional life, and Darwin explores the animal origins of such human characteristics as the lifting of the eyebrows in moments of surprise and the mental confusion which typically accompanies blushing. A German translation of The Expression appeared in 1872; Dutch and French versions followed in 1873 and 1874. A second edition of the book, with only minor alterations, was published in 1890. Since its first publication, The Expression has never been out of print, but it has also been described as "Darwin's forgotten masterpiece".