The visionary German naturalist and polymath Alexander von Humboldt (1769-1859) changed the way we understand the natural world—including his then-radical concept of nature as a complex global entity. In this illuminating biography—one of the New York Times 10 Best Books of 2015 and a finalist for the Andrew Carnegie Medal—Andrea Wulf brings Humboldt's extraordinary life into focus: his prediction of human-induced climate change, his daring expeditions to the peaks of South America and to the steppes of Siberia, his relationships with figures like Simón Bolívar and Thomas Jefferson, and the lasting influence of his writings on Darwin, Wordsworth, Goethe, Muir, and Thoreau.