This is the long-awaited revision of the classic petrology text. Thoroughly expanded and updated,the second edition introduces students to the data of modern petrology,the processes thought to affect the development of most rocks,the origins under current consideration,and the literature of petrology. Clearly and concisely written,the book appeals to students of various academic levels. The text encourages a comprehensive,integrated study of rocks. For example,the book's content and its rock association approach together permit students to anticipate not only the mineralogy and chemistry of a rock,but provide an understanding of plausible processes and origins relevant to that rock. An excellent and extensive reference list points out important original sources and enhances the text's appeal as a professional reference book. The second edition includes a new emphasis on plate tectonics. Descriptive sections on various kinds of igneous rocks and modern ideas regarding rock genesis and plate tectonic theory have been added. More than two-thirds of the diagrams and photographs are new to this edition. The photographs,predominantly taken by the author,provide images of outcrops of many kinds of rocks and illustrate important relationships that may not be familiar to most students.