Time-Life Book series entitled Planet Earth; this volume featuring Underground Worlds. Explorers of a stygian realm; the birth of speleology; "In the grip of the demon adventure;" masters of making do; the sporting Essays The lure of the abyss; Europe's premier show cave; a profusion of water-worked wonders; a caver's inventive gear; the hardy denizens of darkness; and a new continent of Karst.
