This is the best textbook I've ever read. The mix of theory and practice, examples and math, and the ordered introduction of concepts flows so well it reads like a treasure quest. Everything has its place, and the place is known - you just have to follow the signs and keep an eye out for those which are subtler than others, just to keep things alive and interesting. It's indicative of the clarity of thinking and broad sweep of this work that you would refer to it (I do and other students I know as well), for other subject matter such as communications, linear algebra, digital filters, probability and control theory. The homework problems are not just a series of one-liners as in most graduate level text books, but well-marked road maps addressing points discussed in the text and opening up new possibilities. The computer projects are very well commented and the results analysed. The language is concise yet fluid, and there are extremely few typos of any kind. This is a very, very high quality work.