The American Practical Navigator, first published in 1802, was billed as the “epitome of navigation” by its original author, Nathaniel Bowditch, an early American mathematician who is often considered the founder of modern maritime navigation. The text, often colloquially referred to simply as “Bowditch,” has evolved with the advances in navigation practices since that first issue and continues to serve as a valuable reference for marine navigation in the modern day. In the more than 210 years since Bowditch first published it, there have been an estimated million copies in print over the course of more than fifty editions. This latest edition—fully updated by the U.S. government to reorganize the topics, delete obsolete text, and incorporate the extensive changes in navigation that have occurred in the electronic age—remains popular with sailors of all types, is carried onboard every commissioned U.S. Navy vessel, and belongs in every navigator’s library. The American Practical Navigator describes in detail the principles and factors of navigation, including piloting, electronic navigation, celestial navigation, mathematics, safety, oceanography, and marine meteorology. It also contains a maritime glossary and dozens tables used in typical navigational calculations and solutions, including the formulas used to derive the tabular data. “Bowditch” is a must-have book for every mariner.