By the time his epic five-year voyage on HMS Beagle came to an end in October 1836, Darwin was already a celebrity. His mentor John Stevens Henslow had seen to that, by distributing a pamphlet of Darwin's letters among selected naturalists. Back in England Darwin, after a brief visit to the family home in Shrewsbury, hurried to Cambridge. There he sought advice from some leading scientists on how he should organize the remarkable collection of specimens he had brought with him, which included fossils and stuffed birds. With financial support from his father, Darwin was able to become an independent gentleman scientist.
In 1839 Darwin published “A Naturalist’s Voyage Round the World in HMS Beagle”. The book is both a vivid and exciting travel memoir and a detailed scientific journal. It is an intelligent work, and at times quite humourous. His five-year voyage on HMS Beagle had established Darwin as an eminent scientist; now, with the publication of the journal of his voyage, he also became a popular author.
In London, where he continued his research, Darwin read,among other books, Malthus's “An Essay on the Principle of Population”. What he learned from it would be crucial to his own future work. As Darwin would later write in his autobiography, concerning the struggle for existence among animals and plants: “It at once struck me that … favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species.”
Following his return home from his voyage, Darwin began commenting critically on the Bible as an account of history. Over the next few years, he would go even further – questioning the fundamental principles on which Christianity and other religions were founded. To Darwin, natural selection produced the benefit of adaptation while removing the need for design. Moreover, he professed that he could not see the work of an omnipotent deity in all the pain and suffering in the world. In 1879 he wrote the following: "I have never been an atheist in the sense of denying the existence of a God.–I think that generally ... an agnostic would be the most correct description of my state of mind."