Patricia Daniels is an author and editor for National Geographic who has written, edited, or contributed to books on history, science, and geography, most recently the "National Geographic Encyclopedia of Space." She lives in State College, Pennsylvania. Stephen G. Hyslop has been a writer and editor for Time-Life Books and National Geographic, as well as author of "Bound for Santa Fe" and "Chroniclers of Indian Life." He lives in Virginia. Douglas G. Brinkley is the director of the Theodore Roosevelt Center for American Civilization and Professor of History at Tulane University. He au...