"Any kind of boating can be fun," the author points out, "racing around the marks, or coastwise cruising where there is almost always at hand visual reference ashore from which bearings can be taken for locating one's position and thus finding one's way home. Severing these ties with land, however, offers a new kind of fun, a new kind of freedom, a freedom from dependence on land." Here is a basic beginner's book, introducing the amateur to the tools, the vocabulary, and the techniques of celestial navigation. Among the recommended tools are the H. O. 249 tables, the most widely used among amateur navigators at sea because of their simplicity. The ability to determine one's position at sea both liberates the sailor from the land and enables him to find his way to his destination. If you can read, add and subtract, understand angles, and use a protractor, you can learn to navigate in your armchair or at sea from Celestial Navigation by H. O. 249.