Stephen Ambrose wrote books that both celebrated American achievements and illuminated the humanity and inherent fallibility of those whom he portrayed. While many of Ambrose's best known books dealt with the military and its conduct in war, most notably, Band of Brothers, D-Day: June 6, 1944, and The Wild Blue: The Men and Boys who Flew the B-24s over Germany, Ambrose also wrote a number of biographies, including of Richard Nixon and Henry Halleck. The 1996 publication of Undaunted Courage: Meriweather Lewis, Thomas Jefferson, and the Opening of the American West was consistent with the author's interest in personal, political and military courage, and on the factors that contributed to displays of heroism and fortitude.
The title of Ambose's book was taken from Thomas Jefferson's description of Meriweather Lewis, the soldier and explorer who the president chose to lead an exceptionally bold and dangerous mission to explore unknown territories well beyond American boundaries:
"Of courage undaunted, possessing a firmness and perserverence of purpose which nothing but impossibilities could divert from its direction, careful as a father of those committed to his charge, yet steady in the maintenance of order and discipline, intimate with Indian character, customs, and principles . . ."
To President Jefferson, whose purchase of the Louisiana territories would follow the Lewis and Clark expedition, Lewis possessed all of the characteristics necessary to lead that expedition. In addition to his military background and proven leadership abilities, Lewis was also possessed of a level of intellectual curiosity and knowledge of nature that appealed to Jefferson. To quote the president on Lewis again, "I could have no hesitation in confiding the enterprise to him." The teaming of Lewis and William Clark, another soldier and explorer experienced at interacting with Native Americans, would prove highly beneficial when it came time to undertake the actual mission to explore the Spanish and French territories that would soon be incorporated into the United States.
While Ambrose provides illuminating insights into the men who led the expedition, it could be said that his main goal in writing Undaunted Courage was to further illuminate the contributions of Thomas Jefferson, who not only conceptualized the mission but made certain that is would be carried out, all the while wary of British intentions. Ambrose was known to be critical of historians and political scientists who marginalized the contributions of America's founders, including Jefferson and George Washington, on account of their histories as slave-owners, and, with Undaunted Courage, sought to force Jefferson's foresight and leadership back into the limelight. Ambrose did not ignore and was unapologetic regarding the flaws in these men's characters, and he unarguably condemned the institution of slavery as practiced in the 17th and 18th Centuries. What he intended was inject balance back into discussions of American history. In a 2002 article for Smithsonian magazine, Ambrose restated the case for Jefferson's greatness:
"The Washington Monument and the Jefferson and Lincoln memorials remind us that greatness comes in different forms and at a price. Jefferson, by his words, gave us aspirations. Washington, through his actions, showed us what was possible. Lincoln's courage turned both into reality."