Personal Narrative of Travels to th Equinoctial Regions of America

All three volumes, covering the expedition of 1799-1804. According to Wikipedia: "Friedrich Wilhelm Heinrich Alexander von Humboldt (September 14, 1769 – May 6, 1859) was a Prussian geographer, naturalist and explorer, and the younger brother of the Prussian minister, philosopher and linguist Wilhelm von Humboldt (1767–1835). Humboldt's quantitative work on botanical geography laid the foundati...