To be prepared for calculus a student needs not only technical skill but also a clear understanding of concepts. Indeed, conceptual understanding and technical skill go hand in hand, each reinforcing the other. A student also needs to gain experience in problem-solving, as well as an appreciation for the power and utility of mathematics in modeling the real world. Every feature of this textbook is devoted to fostering these goals. In this Eighth Edition our objective is to further enhance the effectiveness of the book as a teaching tool for instructors and as a learning tool for students. Many of the changes in this new edition are a result of suggestions we have received from instructors and students who are using the current edition, recommendations from reviewers, insights we have gained from our own experience teaching from the text, and conversations we have had with colleagues and students. In all the changes, both small and large, we have retained the features that have contributed to the success of this book. -- Preface.