Dennis E. Showalter is a professor of history at Colorado College who specializes in German military history. He was president of the American Society for Military History from 1997 to 2001. In addition, Showalter is an advising fellow of the Barsanti Military History Center at the University of North Texas. Showalter has previously taught at the United States Air Force Academy, the United States Military Academy, and the Marine Corps University. He has written extensively on the wars of Frederick the Great, the German Wars of Unification, World War I, and World War II. Tannenberg won the American Historical Association's Paul M. Birdsall Prize for best new book of 1992.
- "Manifestation of Reform: The Rearmament of the Prussian Infantry, 1806-13," The Journal of Modern History Vol. 44, No. 3, September 1972
- Railroads and Rifles: Soldiers, Technology, and the Unification of Germany. Hamden, Connecticut: Archon/Shoe String, 1975. ISBN 0-208-01505-1
- Tannenberg: Clash of Empires, 1914. Hamden, Connecticut: Archon, 1991. ISBN 978-0-208-02252-3. Repr. Washington: Brassey's, 2004. ISBN 978-1-57488-781-5
- The Wars of Frederick the Great. London/New York: Longman, 1996. ISBN 978-0-582-06260-3
- The Wars of German Unification. London: Arnold, 2004. ISBN 978-0-340-73210-6
- (with William J. Astore) Hindenburg: Icon of German Militarism. Military Profiles. Washington: Potomac, 2005. ISBN 978-1-57488-653-5
- Patton and Rommel: Men Of War in the Twentieth Century. New York: Berkley Caliber, 2005. ISBN 978-0-425-19346-4