The thirteenth edition of Essentials of Geology, like its predecessors, is a college-level text that is intended to be a meaningful, nontechnical survey for students taking their first course in geology. In addition to being informative and up-to-date, a major goal of this book is to meet the need of students for a readable and user-friendly text that is a valuable tool for learning the basic principles and concepts of geology.
Although many topical issues are treated in the 13th edition of Essentials, it should be emphasized that the main focus of this new edition remains the same as the focus of each of its predecessors: to promote student understanding of basic principles. As much as possible, we have attempted to provide the reader with a sense of the observational techniques and reasoning processes that constitute the science of geology.

Why do earthquakes, volcanoes, floods, and landslides happen? What causes mountains to rise? How do beautiful landscapes develop? How have climate and life changed through time? When did the Earth form, and by what process? Where do we dig to find valuable metals, and where do we drill to find oil? Does sea level change? Do continents move? The study of geology addresses these important questions and many more. But from the birth of the discipline, in the late 18th century, until the mid-20th century, geologists considered each question largely in isolation, without pondering its relation to the others.

The 12th edition of Essentials of Geology, like its predecessors, is a college-level text for students taking their first and perhaps only course in geology. The text is intended to be a meaningful, nontechnical survey for people with little background in science. Usually students are taking this class to meet a portion of their college’s or university’s general requirements.
In addition to being informative and up-to-date, a major goal of Essentials of Geology is to meet the need of beginning students for a readable and user-friendly text; a text that is a highly usable tool for learning the basic principles and concepts of geology <...>

Petrology, from the Greek words petra , meaning rock, and logos, meaning knowledge, is the study of rocks and the conditions in which they form. It includes igneous, metamorphic, and sedimentary petrology.