At the USCG Auxiliary we use this text as the base of the Public Education course bearing the same name. I'm instructor for that course and haven't found any other resource that can hold a candle to it. It is very detailed and explains concepts in an easy to understand way. My only complaint is not with the author, but with GPS manufacturers. Most GPS receivers and Radar units rely -maybe because of reliability, I don't know- on (few) buttons based User Interface instead of touchscreen. This requires to bury all commands and configurations in a maze of menus that are unlikely to be remembered. The book uses quite a bit of real estate in dealing with the menus of different GPS receivers and chart-plotters that may or may not coincide with what you have. From my perspective GPS manufacturers will be wise to subcontract the User Interface design to developers seasoned in mobile apps. The world of mobile device navigation is improving the usability at a fast pace.
Otherwise, the book is well organized and the navigation methodology is sound.
NOTE: The space segment page of gps.gov states that the orbit period is "twice a day" and not 24 hours as stated in the book.