In the following review, Viola finds that "Ambrose presents a carefully-written, well-balanced find thoroughly researched biography of Lewis as well as a compelling history of the expedition."

Thomas Jefferson, the grand architect of Manifest Destiny, ventured no farther west than the Blue Ridge Mountains, yet he determined the westward course of American expansion as deftly as he charted his country's route to political independence. Our nation's territorial growth in large part is owing to Jefferson's vision, pragmatism, and, perhaps most important, scientific curiosity. His eyes to the West were provided by his protegé Meriwether Lewis who, with his companion William Clark, unlocked the secrets of the trans-Mississippi West.

Jefferson had looked longingly toward the West for many years, but not until he became president could he turn his dream into a reality. The Louisiana Purchase was fortuitous, but Jefferson would have sent an expedition to the...