This treatment develops the real number system and the theory of calculus on the real line, extending the theory to real and complex planes. Designed for students with one year of calculus, it features extended discussions of key ideas and detailed proofs of difficult theorems. 1991 edition.
Not for the average reader, but fantastic from cover to cover to understand the foundation of everyday mathematics. Great introduction book that bridges the gap from your everyday calculus/multivariable calculus to formal proofs.