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 be impossible." He asked Hooker how many pages would be available, but "If the Referees were to reject it as not strictly scientific I would, perhaps publish it as pamphet." He began his "abstract of Species book" on 20 July 1858, while on holiday at Sandown, and wrote parts of it from memory, while sending the manuscripts to his friends for checking. By early October, he began to "expect my abstract will run into a small volume, which will have to be published separately." Over the same period, he continued to collect information and write large fully detailed sections of