Focusing on the "why's" of mathematics rather than the "how's," the unique approach of this text will appeal to a wide range of readers, from those taking a first course in calculus to those seeking deeper insights or needing a transition from calculus to analysis. The author takes care to supply strong motivations for abstract concepts, thereby helping beginners overcome the intimidation often felt when first confronting abstraction. While emphasizing the "why's," the book does not entirely neglect the "how's" and provides sufficient exposure to the techniques through numerous exercises, with answers supplied in the back of the book.