My first book had a perilous childhood. With this new edition, I hope it has reached a secure middle age. The book was born in 1969 as an "innovative text­ book"-a breed everyone claims to want but which usu­ ally goes straight to the orphanage. My original plan had been to write a small supplementary textbook on differen­ tial forms, but overly optimistic publishers talked me out of this modest intention and into the wholly unrealistic ob­ jective (especially unrealistic for an unknown 30-year-old author) of writing a full-scale advanced calculus course that would revolutionize the way advanced calculus was taught and sell lots of books in the process. I have never regretted the effort that I expended in the pursuit of this hopeless dream-{}nly that the book was published as a textbook and marketed as a textbook, with the result that the case for differential forms that it tried to make was hardly heard. It received a favorable tele­ graphic review of a few lines in the American Mathematical Monthly, and that was it. The only other way a potential reader could learn of the book's existence was to read an advertisement or to encounter one of the publisher's sales­ men. Ironically, my subsequent books-Riemann :S Zeta Function, Fermat:S Last Theorem and Galois Theory-sold many more copies than the original edition of Advanced Calculus, even though they were written with no commer­ cial motive at all and were directed to a narrower group of readers.