This book is an old classic in fourier analysis - it emphasizes intuitive understanding and uses images a lot to convey information, e.g. the book includes a pictorial dictionary of fourier transforms, and recommends using the method of dragging a strip of paper to get a better understanding of convolutions. The problems are challenging and very interesting, e.g. one problem asks the reader to explain the differences in spectra when reconstructing a signal by linear interpolation vs. sketching a smooth graph between the sample points by hand. (there are also easier problems for to begin with, before one tackles "engineering" questions as the one above) Highly recommended!

When I came to the field of Fourier transform, the book provides me a clear, easy-understanding picture to the field so that I believe any of you can get into the field by use of the book. If you are looking for your first book to Fourier transform, don't waste your time, it is. Even through my life in the research, I depended on it most of the time. It's too great.

If you are looking for thorough explanations with great physical insight - this is the book to get. It is for people who want to know WHY more than HOW. However, If you are looking for how (to implement), I suggest the book "Fast Fourier Transform" by Brigham