Humboldt and Jefferson explores the relationship between two fascinating personalities: the Prussian explorer, scientist, and geographer Alexander von Humboldt (1769-1859) and the American statesman, architect, and naturalist Thomas Jefferson (1743-1826). In the wake of his famous expedition through the Spanish colonies in the spring of 1804, Humboldt visited the United States, where he met several times with then-president Jefferson. A warm and fruitful friendship resulted, and the two men corresponded a good deal over the years, speculating together on topics of mutual interest,...