The second edition of Principles of Igneous and Metamorphic Petrology follows the same general approach as the first edition. The book is designed to introduce igneous and metamorphic petrology to those who have completed introductory college-level courses in physics, chemistry, and calculus. Its emphasis is on principles and understanding rather than on facts and memorization. With this approach, it is hoped that students will not only gain a sound understanding of petrology but will develop skills that can be applied to the analysis of problems in many other fields of Earth Science.

Anthony Philpotts took many years to write the first edition of the book, and the thought of preparing a revision was daunting. He was therefore grateful when Jay Ague agreed to share the challenge of producing the revised edition. We both share the same approach to the teaching of petrology, and consequently the new edition retains the flavor of the original while benefiting from the dual authorship.

The first edition of the book was written during the 1980s (published 1990). Since then, the field of petrology has seen significant changes due to both increased knowledge of our planet and new research techniques. In preparing a book of this scope, one cannot help but reflect on the status of petrology as a field of scientific endeavor, especially in light of the trend at many universities to give only survey courses in petrology that are geared toward the environmental science student.