....An excellent book on navigation-
"Finding Your Way Without Map or Compass" by Harold Gatty, Dover Publications.
Mr Gatty was Wiley Post's navigator on a record setting round the world flight in 1931; his book, republished by Dover in 1999, was originally entitled "Nature is Your Guide: How to Find your way on Land and Sea by Observing Nature", was first in print in 1958.
A very interesting and useful book. many non traditional methods of navigation discussed.
If you ever wanted to know how to navigate reading the nuances of sea ice reflection, or the habits of sea birds or the shapes of trees, this'd be a must read.