This book explains mathematics essential to flight navigation in classic general and philosophical approach similar to "Stick and Rudder" and "Weather Flying", teaching basic principles and reasoning. It assumes little mathematical background but takes a simple straightforward approach to nav maths that combines ancient celestial forms upon which new technologies are based. The book provides an understanding of navigation that allows pilots to exploit full powers of new technologies and presents techniques of GPS and other nav forms, including calculations of distance and bearings. Also included are chart construction, errors, uses, and magnetic compass, errors and uses, together with mental calculations and rules of thumb. Flight planning, especially long-range, is also covered.