This book is a firsthand account of exploring the earth’s final frontier: The hidden depths of our oceans and the sunken caves inside our planet. From one of the top cave divers working today — and one of the very few women in her field — Into the Planet blends science, adventure, and memoir to bring readers face-to-face with the terror and beauty of Earth’s remaining unknowns and the extremes of human capability, according to a review published on goodreads.com. Written with hair-raising intensity, it is the first book to deliver an intimate account of cave diving, transporting readers deep into inner space, where fear must be reconciled and a mission’s success balances between knowing one’s limits and pushing the envelope of human endurance. Jill Heinerth—the first person in history to dive deep into an Antarctic iceberg and leader of a team that discovered the ancient watery remains of Mayan civilizations—has descended farther into the inner depths of our planet than any other woman. While Heinerth swims beneath our feet in the lifeblood of our planet, she works with biologists discovering new species, physicists tracking climate change, and hydrogeologists examining our finite freshwater reserves.