The author has provided a shop window for some of the ideas, techniques and elegant results of Fourier analysis, and for their applications. These range from number theory, numerical analysis, control theory and statistics, to earth science, astronomy, and electrical engineering. Each application is placed in perspective with a short essay. The prerequisites are few (the reader with knowledge of second or third year undergraduate mathematics should have no difficulty following the text), and the style is lively and entertaining.
I did not read this book from cover to cover, because that would not have been true to the spirit in which it was written. I had to read more than a few chapters before it clicked: this book is a buffet... no, a smorgasbord! The breadth of topics treated here is incredible, especially considering how well they are bound together by their common theme (as given in the title). Several distinct threads run through the book, in a way that makes jumping around from chapter to chapter easy and rewarding.
This is not the place to go for all the (gory) analytic details about exactly when and how various thing converge. The theory is investigated in detail just when it's interesting to do so (which means your enjoyment of this book will depend on the compatibility between your taste and the author's).
Applications-related topics that get their own chapter(s) include: Monte Carlo methods, mechanical linkages, the debate over the age of the Earth in the 19th century, the laying and operation of the first transatlantic cables, stability of control systems, statistical data analysis for fraud detection, estimating the diameters of distant stars, and coding theory.