On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection Letter" from Darwin to Asa Gray. This was the first announcement of the Darwin – Wallace theory of evolution by natural selection; the papers appeared in print on 20 August 1858. The presentation of the papers spurred Darwin to write a condensed "abstract" of his "big book" on "Natural Selection". This was published in November 1859 as "On the Origin of Species". On the voyage of the "Beagle" the young Charles Darwin took a break between graduating and starting his career as a clergyman to study the natural history of South America, an interest he had developed at the University
On the Origin of Species Darwin had been somewhat coy about human origins, not identifying any explicit conclusion on the matter in his book, he had dropped enough hints about human's animal ancestry for the inference to be made, and the first review claimed it made a creed of the "men from monkeys" idea from "Vestiges". Human evolution became central to the debate and was strongly argued by Huxley who featured it in his popular "working-men's lectures". Darwin did not publish his own views on this until 1871. The naturalism of natural selection conflicted with presumptions of purpose in nature and while this could be