In 1926, twenty-three-year-old cub newspaper reporter Leslie McFarlane responded to an ad: "Experienced Fiction Writer Wanted." The ad was signed by Edward Stratemeyer, whose syndicate effectively invented mass-market children's book publishing in America. McFarlane, who had a few published adventure stories to his name, was hired and his first job was to write Dave Fearless Under the Ocean as Roy Rockwood--for a flat fee of $100, no royalties...