When President Thomas Jefferson dispatched Captains Meriwether Lewis and William Clark on their great exploratory expedition of the lands west of the Mississippi, the journey was destined to become the most famous and significant American land expedition in history. Jefferson must have realized the timeless importance of the mission, for he urged the captains to keep multiple records of all they saw and experienced during the journey. Those records, dutifully kept from the departure of the expedition in 1803 to its conclusion in 1806, provided invaluable information about the wonders of the American West. In the next 150 years the journals were published in several versions scrupulously authentic, dubiously revised, and complacently counterfeit. This book is the first comprehensive account of the various versions and of the persons responsible for them. It tells of the dedicated scholarship, inspired judgment, and exciting discovery of new materials, as well as the misguided enthusiasm and journalistic skulduggery that marred the publishing history of the journals, field notes, and letters of members of the expedition. The author breaks new ground in his use of previously unpublished letters written by the editors of the two major editions. An appendix introduces a recently discovered manuscript version of the journal kept by one of the expedition members. The book also includes an appraisal of books and articles written about the expedition and a resume of the illustrative materials, sketches, and maps that enriched the accounts. A History of the Lewis and Clark Journals is thus itself a significant expedition into a historic period in America's past.