In this little volume I have endeavoured to present the life and work of Charles Darwin viewed as a moment in a great revolution, in due relation both to those who went before and to those who come after him. Recognising, as has been well said, that the wave makes the crest, not the crest the wave, I have tried to let my hero fall naturally into his proper place in a vast onward movement of the human intellect, of which he was himself at once a splendid product and a moving cause of the first importance.