The Expression of the Emotions in Man and Animals public by arguing that humans had "animal traits", and instead charmed them by telling stories of "human traits in animals", thus avoiding too much explicit talk of natural selection at work. Darwin preferred to leave the evolutionary implications hanging. Korn points out that the book has never been out of print since 1872, calling into question Ekman's talk of "Darwin's lost masterpiece". The "Editor's notes" at the "Mead Project source page" on the book comment that Darwin concluded work on the book with a sense of relief. The proofs, tackled by his daughter Henrietta ("Ettie") and son Leo, required a
The Variation of Animals and Plants under Domestication grown too long, & I think I shall publish separately a very small volume, 'an essay on the origin of mankind'". This "essay" would become two books: "The Descent of Man, and Selection in Relation to Sex" (1871) and "The Expression of Emotions in Man and Animals" (1872). The book had been advertised as early as 1865 with the unwieldy title "Domesticated Animals and Cultivated Plants, or the Principles of Variation, Inheritance, Reversion, Crossing, Interbreeding, and Selection under Domestication" but Darwin agreed to the shorter "The Variation of Animals and Plants Under Domestication" suggested by the compositors. By May he