This book is the final work of the great American historian who opened up a new period in interpreting the history of the United States by emphasizing the importance of the frontier in shaping American culture. Professor Turner wrote The United States 1830-1850 over a fifteen-year period before his death in 1932 and many consider it his major work. As Crane Brinton wrote in the Christian Science Monitor at the time of its publication, "This is the long-awaited master work of a man who.must certainly figure in any list of great American historians." Turner was interested in the two decades between 1830 and 1850 because he felt they constituted a distinct era in which regional geography played a significant role in the development of the country. "Whether we consider politics, inventions, industrial processes, social changes, journalism, or even literature and religion, the outstanding fact is that, in these years, the common man grew in power and confidence, the peculiarly American conditions and ideals gained strength and recognition. An optimistic and creative nation was forming and dealing with democracy and with things, in vast new spaces, in an original, practical, and determined way and on a grand scale." This, in Professor Turner's works, is the theme of United States 1830-1850.