With its warm, dry climate and abundance of caves and rockshelters, the Southwest is a repository of fossils that provide unparalleled opportunities to study the ancient past. During the last ice age - more than 10,000 years ago - the desert regions of the American Southwest flourished, with conifer woodlands blanketing a landscape where camels, mammoths, dire wolves, short-faced bears, and ground sloths thrived. Recreating the past landscape and life forms of the Southwest, this guidebook examines a pivotal period in the ecological history of five southwestern national parks - Canyonlands, Grand Canyon, Chaco Canyon, Mesa Verde, and Big Bend - recounting as well the coming of humans to the region and the ascendance of the ecosystems we see today. Drawing on fossil evidence from cave sediments and packrat middens - collections of plants, insects, and vertebrate bones - Scott A. Elias describes how the increased precipitation and cooler temperatures of the Pleistocene affected the desert environment. He also traces the impact of ancient cultures on the landscape, from the earliest inhabitants to the Anasazi. Surveying the basic types of vertebrate, insect, and plant fossils and outlining dating methods as well as other field techniques, the book covers geology, climate, and paleoecology - the interactions among prehistoric plants and animals. For hikers, tourists, and amateur paleontologists, Elias opens a window onto the natural history of one of America's most dramatic regions.