Zadok Cramer was a Pittsburgh printer and bookbinder who in 1801 began publishing the best known of the early river guides, The Navigator. He originally intended it as a handbook for western immigrants, but it became the bible for early flatboatmen and keelboatmen, many of whom went on to become steamboat pilots.

The Navigator was a compilation of travelers’ journals and reports which gave “directions for navigating the Monongahela, Alleghany, Ohio, and Mississippi Rivers” with descriptions of villages, settlements, harbors, and distances between points. Beginning with the fifth edition in 1806, this important river guide contained woodcut river charts showing islands, channels, and obstructions to navigation. In all, twelve editions were published between 1801 and 1824, and the works were followed by many imitators who openly plagarized or leaned heavily on his book for information.

The Navigator proved to be extremely useful to settlers and river traders alike, and it greatly influenced western migration. Today, the different editions are a goldmine of information for historians as they span such developments as the invention of the steamboat and the discoveries of Lewis and Clark.