Portney's Ponderables

"Navigation puzzles, controversies, historical problems, and other ponderables demystified by an expert navigator and writer. Joe Portney is a US Naval Academy graduate and Air Force navigator who has participated in three historic flights over the North Pole. He is a past President of the Institute of Navigation and recipient of the Weems Award for continuing contributions to the art and science of navigation. He has produced a wonderful little book here, chock filled with interesting tidbits, each of which can be read in a few minutes but will stimulate your thought for many days to come. Some are very basic, others more involved, but he provides a clear explanation of each. Some refer to math computations that we might not all be familiar with, but this is not a distraction from the main points being made even in these few cases."