[CRAMER, Zadok, pub]. The Navigator: Containing Directions for Navigating the Monongahela, Alleghany[sic], Ohio, and Mississippi Rivers...To Which is Added An Appendix, Containing An Account of Louisiana, and of the Missouri and Columbia Rivers, As Discovered by the Voyage Under Captains Lewis and Clark. Pittsburgh. 1808. ,156pp. including twenty-eight full-page maps. 12mo.Contemporary half calf and paper boards. Lower outer corner of rear board creased, boards worn at extremities. Bookplates on front pastedown and front free endpaper, early ownership inscriptions on front flyleaves. Occasional light fox marks, some light tanning. Page 147-148 with a closed tear, with no loss. A few leaves with neat repairs along the foredge. Overall, about very good. In a half morocco and green cloth folding box, spine gilt. HOWES C855, "aa." SABIN 17385. LITERATURE OF THE LEWIS & CLARK EXPEDITION, pp.89-94. Styled the "Sixth edition - improved and enlarged" on the titlepage, but actually only the fourth known edition, after those of 1802, 1804, and 1806. The first two editions have been found in a few copies only. Cramer's work is the first navigational guide for the Ohio and Mississippi rivers, which were vitally important commercial arteries at the time. The present edition is the first to contain material regarding the Lewis and Clark expedition, found on the final ten pages of text. The Lewis and Clark material is taken from Patrick Gass' journal, which was also printed by Zadok Cramer in Pittsburgh the previous year. Also included are twenty-eight woodcut maps of various sections of the rivers described. A vitally important work in helping to develop the commerce of the early United States, with a very early account of Lewis and Clark's discoveries.