I read this mostly as a "warm-up" for my Area Exam, the last part of my Ph.D. quals. I've used it as a reference for four years but had never read it cover-to-cover. Doing so was somewhat rewarding, giving me some additional insight into a number of topics I thought I understood. In about two weeks I read all but the last chapter — the one on homomorphic signal processing (the cepstrum, etc.) — which I decided to put off until after my Area Exam since I want to look at it carefully. I give this textbook a mediocre rating because I think it is decent as a reference but not a great way to learn the material from scratch. I wish I knew of a better reference, but this is actually one of the better ones I've seen.