The German geologist Leopold von Buch (1774–1853) was a fellow-student of Alexander von Humboldt, with whom he later did fieldwork that led to important advances in the understanding of the Jurassic system and the origins of basalt. In 1815 Buch and the Norwegian botanist Christian Smith spent several months in the Canary Isles, and the resulting book, which appeared in 1825, is one of Buch's most important publications. It contains three papers Buch had previously published in journals, on flora (1816), the 1730 eruption on Lanzarote (1818) and temperature (1820), with additional chapters on population, land area and economics, the measurement of altitude, mineralogy, and detailed comparative data on volcanoes around the world. The substantial introduction includes a journal that records Buch's enthusiasm for the islands' scenery, natural history and people, and an obituary of Smith, who died in 1816 on a research trip to the Congo.