The All-Story Magazine, Dec 1913

A helmeted warrior grips a long lance while embracing a fair-haired woman in a star-spangled robe, her chained wrist raised toward a pale sky — the Christmas issue cover for Edgar Rice Burroughs's Warlord of Mars, serialized here as the third John Carter novel. The cover-lines announce it plainly: THE ALL-STORY / WARLORD OF MARS / 15 CENTS, with a note that this is a sequel to Under the Moons of Mars and The Gods of Mars. Wood-pulp magazines like All-Story were the engine of American genre fiction — cheap paper, painted covers, breathless plotting — and Burroughs built planetary romance almost single-handedly in their pages. The genres comic books later claimed as their own — science fiction, sword-and-sorcery — were born here.