Robert L. O'Connell received a Ph.D. in history at the University of Virginia, and spent thirty years as a senior analyst at the National Ground Intelligence Center. He is presently a visiting professor at the Naval Postgraduate School, and was a contributing editor to MHQ: The Quarterly Journal of Military History. He is the author of numerous books, including The Ghosts of Cannae: Hannibal and the Darkest Hour of the Roman Republic; Of Arms and Men: A History of War, Weapons, and Aggression; and Soul of the Sword: An Illustrated History of Weaponry and Warfare from Prehistory to the Present.