This text treats the development of geological ideas, from antiquity to the present. The significance of ideas about the earth is reflected in the range of thinkers who have written on geological questions: for example, Aristotle and Descartes, with their ideas grounded in philosophy; Werner, with ideas developed as an outgrowth of the German mining tradition; Humboldt, with his effort to produce a holistic picture of nature; Lyell, with his ideas on the earth's age and history; Jeffreys, with his geophysics; and Lovelock, with his Gaia hypothesis. Beginning with a discussion of organic views of the earth in mythopoeic cultures, the book traverses such topics as mechanical and historicist views of the earth, map-work, chemical analyses of rock and minerals, geomorphology, experimental petrology, seismology, theories of mountain building, sedimentology, and geochemistry, and brings us back to the idea that the earth may, in a sense, be regarded as a living entity, or at least that life is an essential feature of its behaviour.