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). Originally intended as a section of The Descent of Man, it was published separately in 1872 and concerns biological aspects of behaviour. In this book, Darwin sets out some early concepts of behavioural genetics, and explores the origins of such human characteristics as the pursing of the lips in moments of concentration and the mental confusion which typically accompanies blushing. A German translation of The Expression appeared in 1872; Dutch and French translations followed in 1873 and 1874. A second edition of the book was published in 1890.