The origin of the species is a book by Charles Darwin published on November 24, 1859, considered one of the precursor works of scientific literature and the foundation of the theory of evolutionary biology.

Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process known as natural selection. He presented evidence that the diversity of life emerged from common descent through a branched pattern of evolution. Darwin included the evidence he gathered in his expedition on the voyage of the Beagle in the 1830s and his subsequent discoveries through research, correspondence and experimentation.