If you loved how Tom Billings heads into the unknown with a single purpose—flying a hydroplane into Caspak to locate Bowen Tyler, then slogging through Kro-lu and Galu lands until the goal is in reach—you’ll click with Challenger’s no-nonsense expedition up to the Amazonian plateau in The Lost World. The stakes are simple and driving, the terrain teems with prehistoric threats, and every chapter pushes the mission forward the way Billings’ trek did once he teamed up with Ajor.

You tore through The People That Time Forgot because it never slows—Billings dodging arrows mid-flight, scrambling from saurian attacks, and barely catching his breath before the next clash. King Solomon’s Mines delivers that same pulp throttle: Allan Quatermain’s party races across deserts and treacherous passes, stumbles into ambushes, and survives tight, swashbuckling escapes with the same relentless snap you enjoyed in Billings and Ajor’s headlong trek.

If Caspak’s evolutionary ladder fascinated you—the way Billings learns how Band-lu become Kro-lu and, ultimately, Galu alongside Ajor—then At the Earth’s Core will scratch the same itch. Burroughs maps Pellucidar with similar care: perpetual noon skies, the telepathic Mahars ruling over Sagoth enforcers, and distinct peoples with their own customs. Like Billings picking up Caspak lore, you’ll explore a fully worked-out world where every creature and tribe fits into a strange, cohesive ecology.

Part of the charm in The People That Time Forgot is how cleanly it moves: Billings arrives, crashes, meets Ajor, and presses on—step by step through prehistoric hazards until the objective is met. Verne’s Twenty Thousand Leagues Under the Seas offers that same clear, linear sweep as Professor Aronnax journeys with Captain Nemo from one marvel to the next, each episode building on the last without narrative tricks—just pure, immersive adventure.

If Ajor won you over—fierce, resourceful, and pivotal to how Billings survives Caspak—then She will intrigue you with Ayesha, a commanding presence whose will and intellect drive the story as surely as any hero’s. While Billings learns to respect Ajor’s knowledge of Galu lands and customs, Haggard’s explorers must reckon with Ayesha’s power and purpose, making her more than a love interest—she’s the fulcrum of the expedition’s fate.