James Stewart has revised this text in North America, retaining the focus on problem solving, accuracy, explanations, and the graded problems. In this edition, Stewart has increased his emphasis on technology and innovation and has expanded his focus on problem solving and applications. When writing his previous editions, Stewart set out to bring some of the spirit of Polya to his presentation. This resulted in the strategy sections in the First Edition and the Problems Plus and Applications Plus in the Second Edition. Now in the Third Edition, he extends the idea further with a new section on Principles of Problem Solving and new extended examples in the Problems Plus sections. Stewart makes a serious attempt to help students reason mathematically.