Your author was chief engineer on the Avionics for the F111 fighter aircraft which was the first military aircraft to include GPS for its navigation system. That was before the days of widespread use of NanoTechology in electronics; as a result the F111 GPS was in a box the size of a Personal Computer and cost around half million dollars. I have a Tom-Tom GPS for my auto which is palm sized and cost a few hundred dollars. In 2012 I bought a 4 inch Samsung SIII smartphone which cost less than $200 and which included a free GPS App. I also bought a Toshiba Thrive Tablet for less than $300 which contains a free Google GPS App. GPS can be downloaded free to any Android mobile device. These free Google GPS Apps use Google navigation maps, for which you get charged data usage by your Android mobile server. You can download a more sophisticated GPS program that includes downloaded maps for which you pay a once only price, which avoids the data cost for using the maps which are stored in your mobile device memory. I took a test flight in the Caltech flying club aircraft that included a GPS navigation system with an easy to comprehend display. One of the benefits of this aircraft GPS is it would permit making IFR approaches to airports that lack an FAA ILS approach system, such as the airport here in Lompoc, CA, where I live. This book is intended to provide the status of GPS technology for use in walking, driving, boating and flying in 2013.