The incalculable influence of Alexander von Humboldt (1769-1859) on biology, botany, geology, and meteorology deservedly earned him the reputation as the world's most illustrious scientist before Charles Darwin. Humboldt's breath-taking explorations of Mexico and South America from 1799 to 1804 are akin to Europe's second "discovery" of the New World - this time, a scientific one. His Political Essay on the Kingdom of New Spain is a foundational document about Mexico and its cultures and is still widely consulted by anthropologists, geographers, and historians. In Humboldt's Mexico, Myron...