This book provides an excellant source of information for the 'principles of operation' of modern avionics systems. Its the first of such texts that I have seen that takes the mystery out of the 'glass' environment. I highly recommend it for pilots trying to gain a better understanding of what is really going on behind the Cathode Ray Tubes and Flight Management Systems. I know of few other texts that provide such well organized information in such a concise collection of subject chapters.