When I was in spirits I sometimes fancied that my book wd be successful; but I never even built a castle-in-the air of such success as it has met with; I do not mean the sale, but the impression it has made on you…& Hooker & Huxley. The whole has infinitely exceeded my wildest hopes.—
(letter to Charles Lyell, 25 [November 1859]).
From a quiet rural existence at Down in Kent, filled with steady work on his ‘big book’ on the transmutation of species, Darwin was jolted into action in 1858 by the arrival of an unexpected letter (no longer extant) from Alfred Russel Wallace outlining a remarkably similar mechanism for species change. This letter led to the first announcement of Darwin’s and Wallace’s respective theories of organic change at the Linnean Society of London in July 1858 and prompted the composition and publication, in November 1859, of Darwin’s major treatise On the origin of species by means of natural selection.