Darwin published On the Origin of Species 23 years after returning from the Beagle voyage. The Beagle returned to England on 2 October 1836, and the first edition of Darwin’s book appeared on 24 November 1859.
The interval was not idle. Darwin spent years publishing geological and zoological results from the expedition, studying specimens, corresponding with other naturalists, and developing evidence for evolution by natural selection. He began privately outlining his species theory in the early 1840s but delayed a full public presentation while he gathered extensive supporting material.
A major turning point came in 1858, when Alfred Russel Wallace sent Darwin an essay describing a similar theory of natural selection. Their ideas were presented jointly to the Linnean Society in July 1858. Darwin then rapidly prepared an “abstract” of his larger unfinished work. The first printing of Origin sold out quickly, making the 23-year gap a useful measure of the long period of research and caution behind the book.