Charles Darwin joined HMS Beagle when he was just 22 at the request of Captain FitzRoy, who wanted to have a naturalist on board. The ship set sail from Plymouth Sound on 27 December 1831 and returned nearly five years later on 2 October 1836. The journey took Darwin from the Cape de Verde Islands to Mauritius, visiting locations as varied as Brazil, Tierra del Fuego, the Galapagos archipelago, South Africa, New Zealand and the Azores.

Darwin's book is a vivid travel diary of this trip with personal anecdotes and observations on religious beliefs and racial typecasting, as well as a detailed scientific field journal covering biology, geology and anthropology. He found bones of extinct mammals, experienced volcanoes and discovered many new bird species. The book was instantly acclaimed and the insights he gained through his investigations eventually led to his theory of natural selection.