Tells you how to swing ship, set up deviation tables and adjust compasses.  It describes the numerous causes of compass error: variation, deviation, misalignment, lazy compass, frozen compass, and intermittent deviation. It begins with the very basics of magnetism and progresses to a working knowledge.
The "quick and easy" tools of Compass Corrector for bearings from the sun, and Skyclock for bearings on Polaris, reprinted in the book give it intrinsic value. No other Almanac is needed! SC, 1997, 70 Pages. SW 0.5 lbs