The first edition of Essentials of Geology--an abridged version of Earth: Portrait of a Planet for courses that require a shorter book--quickly became the bestseller in its market on the strength of the text's seamless integration of traditional geological concepts with the most recent theoretical advances in geology, including the theories of plate tectonics and earth systems science. Retaining the core strengths of the first edition, the second edition has been meticulously revised, adding engaging new material and learning tools. The text's popular art program has been significantly expanded, including new satellite photographs and eighteen new "What a Geologist Sees" illustrations. Additionally, the second edition features the most effective and current multimedia tools available for instructors and students.