Veteran wilderness guide Michael P. Ghiglieri takes you into the unknown—among white-water rapids, crocodiles, hippos, gorillas, lions, and impossible waterfalls. His riveting memoir not only serves up true high adventure, it also presents the ecology, natural history, conservation (or the lack of it), and exploration history of nine far-flung wilderness regions across the globe—including the never-to-be-repeated white-water run on the Colorado River through the Grand Canyon during the Bureau of Reclamation’s 1983 super flood of ninety-seven thousand cubic feet per second; the first summit-to-sea descent of the Alas River exploring Sumatra’s new Gunung Leuser National Park, a last redoubt for wild orangutans and other rare species; and the “impossible” run of the Alsek River from the Yukon to Alaska in the world’s largest international conservation area. Into the Unknown reveals what the natural world looks like through a professional’s eyes during “adventure” travel, when things start sliding toward the edge. This insider memoir recounts ten sagas of extreme expeditions into Earth’s most amazing wilderness regions to illustrate their realities, science, allure, history, risks to life and limb, and ultimate fates. Many of these regions have now vanished to “progress.” Others are imperiled. Only a few are protected. But all are, or were, places where exotic beauty and danger are inseparable.