The Lord of the Rings is an epic high fantasy novel[a] by the English author and scholar J. R. R. Tolkien. Set in Middle-earth, the story began as a sequel to Tolkien's 1937 children's book The Hobbit, but eventually developed into a much larger work. Written in stages between 1937 and 1949, The Lord of the Rings is one of the best-selling books ever written, with over 150 million copies sold. The title refers to the story's main antagonist, Sauron, the Dark Lord who in an earlier age created the One Ring to rule the other Rings of Power given to Men, Dwarves, and Elves, in his campaign to conquer all of Middle-earth.