Charles Darwin, the main proponent of the theory of organic evolution, built up much of his evidence for natural selection while aboard the H.M.S. Beagle on its five-year cruise around the world. Darwin's Voyage was instrumental not only in the establishment of his theory, but also in the rigorous application of the scientific method to nature. Darwin published the theory and the evidence for it in his major work, The Origin of Species. He was so complete and persuasive that he was criticized only on philosophical grounds, not scientific. His work opened many new lines of inquiry and triggered a wave of new biological research.