South America's Andean highlands have seen the rise and decline of several impressive, indigenous civilizations. Separated somewhat in time and place, each developed its distinctive socio-cultural accouterments but all shared a need to adjust to the individual, societal and environmental limitations imposed by life at high altitude. Partial oxygen pressure, temperature and humidity fall systematically as altitude rises, but there are other changes as well. Darwin, Forbes, von Humboldt, von Tschudi and other naturalists of the eighteenth and nineteenth centuries who weaved their way through...