A necessary companion to Darwin's The Origin of Species, it springs from the ingenious mind of one of his closest friends, geologist Charles Lyell, whose theories were a critical influence on Darwin's landmark work. First published in 1863, this exploration of the implications of Darwin's "natural selection" for humans remains one of the clearest, most concise explanations of a foundational branch of modern biology. Eminently insightful, the books sings with a scientific poeticism -- chapter sections have such titles as: . "Works of Art in Danish Peat-Mosses" . "Curiosity awakened by the systematic Exploration of the Brixham Cave" . "Two Species of Elephant and Hippopotamus coexisting with Man in France" . "Extinct Mammalia in the Valley of the Oise" Readers in the sciences are sure to find this essential book a highly engaging one as well. Scottish geologist and natural philosopher SIR CHARLES LYELL (1797-1875) was one of the foremost popularizers of science of his time, and the fundamental scientific concepts he developed continue to shape geology and evolutionary biology today. He also wrote the multivolume Principles of Geology: An Attempt to Explain the Former Changes of the Earth's Surface by Reference to Causes Now in Operation. Craters on Mars and the Moon are named in his honor.