This 2021 edition supersedes all earlier editions of The Hollow Earth or Return to the Hollow Earth.

Two mind-stretching steampunk SF novels in one volume. In The Hollow Earth our young narrator Mason Reynolds leaves his farm, befriends the dissolute Edgar Allan Poe, and falls through a thousand-mile hole in the ice of Antarctica. Astounding adventures in the Hollow Earth ensue. Mason finds Seela, the love of his life. Mason, Seela and Poe make their way back to surface. And then they encounter Poe's double...

In Return to the Hollow Earth, our hero Mason and his wife Seela embark on a return voyage to the Hollow Earth with Edgar Allan Poe, traversing a great maelstrom at the North Pole. The god-like sea cucumbers at the Earth's core have a plan. And when Mason and Seela return to the Earth's surface, they're in Santa Cruz, California—in the year 2018.