I purchased this book because I found myself needing to do some digital signal processing and the FFT gives me anxiety. This book was an excellent and clear introduction to the basics and helped me to develop a much better understanding of the analysis. It's written in a clear style and assumes only very basic knowledge, in fact, I think you could understand much of it without even knowing calculus. I found the author's geometric exposition of aliasing to be particularly helpful.I give the book 5 stars, but the potential reader should be aware that the book is serves as an introduction only. In the course of my analysis I discovered that some other "tricks" were necessary that could only be found in a more advanced DSP book. So, it might be helpful to have a more comprehensive reference at your side when it comes time to actually process your signals.