To effectively introduce core concepts, this first-year survey text shifts the focus from learning terminology to understanding--and observing--the range of earth's geologic processes. The Third Edition retains all the features which have made the text popular among students, while integrating new or enhanced elements and material including a significantly revised art program and a suite of technology supplements. The pedagogical aids which appear throughout help students to assimilate the material and continually reassess their progress. At the end of every chapter, new On-the-Web activities encourage the use of web resources, Learning Actively exercises challenge students to apply their knowledge to their surroundings, and Chapter Summaries are now shorter to allow for faster review. New! The revised art program presents a level of detail appropriate for introductory students, and demonstrates naturalism as well as technical accuracy--ensuring that the basics are skillfully communicated. New! Geology at a Glance sections act as quick, visual reference tools summarizing difficult ideas using figures, photos, and flow charts. New! Highlight boxes are now divided into three categories to actively illustrate the relevance of abstract geologic principles to students' daily lives: Environmental, Earth System Science, and Application/Everyday Interest boxes. New! A strong technology package facilitates learning through interactive tutorials and a web site with ACE self-tests, lab simulations, and a link to www.geologylink.com, Houghton Mifflin's award-winning site for the geology community. Instructors may access PowerPoint slides on the web site, as well as additional classroom resources.