On this day, Charles Darwin published On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life, which immediately sold out its initial print run. By 1872, the book had run through six editions, and it became one of the most influential books of modern times.

Darwin, the privileged and well-connected son of a successful English doctor, had been interested in botany and natural sciences since his boyhood, despite the discouragement of his early teachers. At Cambridge, he found professors and scientists with similar interests and with their help began participating in scientific voyages. He traveled around South America for five years as an unpaid botanist on the HMS Beagle. By the time Darwin returned, he had developed an outstanding reputation as a field researcher and scientific writer, based on his many papers and letters dispatched from South America and the Galapagos Islands, which were read at meetings of prominent scientific societies in London.

Darwin began publishing studies of zoology and geology as soon as he returned from his voyage. Fearing the fate of other scientists, like Copernicus and Galileo, who had published radical scientific theories, Darwin held off publishing his theory of natural selection for years. He secretly developed his theory during two decades of surreptitious research following his trip on the Beagle.

Meanwhile, he married and had seven children. He finally published Origin of Species after another scientist began publishing papers with similar ideas. His book laid the groundwork for modern botany, cellular biology, and genetics. He died in 1882.