Described as craggy, rocky, or glacial, among a host of other descriptors, the Earth's geosphere—that is, its solid foundation—is subject to incredible variation. It is these permutations that inform the study of the geological sciences. This field involves not only the study of rocks, minerals, and landforms, but also that of glaciers, fossils, volcanoes, and other aspects of the Earth's surface. This sweeping volume examines the various branches of the geological sciences, as well as the methods and instruments used by geologists to obtain accurate records of the planet's geological history. Profiles of seminal earth scientists are also included.