An exercise in good taste: selection of topics, exercises/problems, computational example. Maybe the best intro to any subject I've read...better than baby Rudin even. A great deal of affection for the subject shines through, even though the author refrains from the corny humor and rantiness that plague lesser books. Genuinely a stone classic, readable by almost anyone (until you get to the complex analytic bits in the later chapters), and successful in conveying the vibe, beauty, and meaning of its subject.