There are certain books that become a center of gravity for people, a guide to life and to work. For many people, that's the Bible. For American mariners, over the last 200 years, that book has been Bowditch.
Officially, the book is titled The American Practical Navigator, but it's more commonly called Bowditch after Nathaniel Bowditch, the young prodigy who wrote the original 1802 edition. For two centuries, copies of this book have settled themselves onto the bridges of ships circling the globe, and helped guide mariners safely from place to place.