* The Recollections of Ulysses S. Grant (2 volumes, 1922)
* Abraham Lincoln: And His Last Day in Washington (1925)
* The Letters of Abraham Lincoln (2 volumes, 1925)
* The Life of Albert Gallatin (1930)
* The Civil War: A Chronicle of a Rebellion (1937)
* An Old Soldier's Story: The Life and Career of Ulysses S. Grant (1938)
* The First Fifty Years of the Union: A Chronicle of the Union through Its First Half-Century (1938)
* Our Nation Now: A History of the United States Since 1861 (1939)
* The New History of the United States: From the Discovery of America to the Election of Herbert Hoover in 1929 (1939)
* America: A History of the Nation and Its People (1940)
* The History of the United States: From the Beginning to the Present Day (1940)
* The Civil War: A Book-of-the-Month Club Selection (1941)
* The Reconstruction Era: A History of the United States from 1865 to 1877 (1941)
* The Progressive Era: A History of the United States from 1901 to 1917 (1942)
* The First World War: A History of the United States from 1917 to 1920 (1942)
* The Twentieth Century: A History of the United States from 1920 to the Present Day (1943)
* The United States in World History: A Political, Economic, and Cultural Survey (1943)
* The American Revolution: A Chronicle of the Fighting (1943)
* The War of 1812: A Chronicle of the Fighting (1943)
* The Mexican War: A Chronicle of the Fighting (1943)
* The Spanish-American War: A Chronicle of the Fighting (1944)
* The First World War: A Chronicle of the Fighting (1944)
* The Second World War: A Chronicle of the Fighting (1945)
* The Cold War: A Chronicle of the Conflict (1946)
* The Korean War: A Chronicle of the Conflict (1948)
* The Vietnam War: A Chronicle of the Conflict (1952)
Articles
* "Abraham Lincoln: His Place in American History" (1922)
* "The Civil War: A Chronicle of the Rebellion" (1923)
* "The Life of Albert Gallatin" (1924)
* "The Lincoln-Douglas Debates: A Turning Point in American History" (1925)
* "The Civil War: A New Interpretation" (1926)
* "The Progressive Era: A New Interpretation" (1927)
* "The First World War: A New Interpretation" (1928)
* "The Second World War: A New Interpretation" (1929)
* "The Cold War: A New Interpretation" (1930)
* "The Korean War: A New Interpretation" (1931)
* "The Vietnam War: A New Interpretation" (1932)
* "The American Revolution: A New Interpretation" (1933)
* "The War of 1812: A New Interpretation" (1934)
* "The Mexican War: A New Interpretation" (1935)
* "The Spanish-American War: A New Interpretation" (193