Lt. Col. Dave Grossman, U.S. Army (Ret.), is an internationally recognized scholar, author, soldier, speaker, and one of the world’s most foremost experts in the field of human aggression, the roots of violence, and violent crime. As an Airborne Ranger infantry officer, and a prior-service sergeant and paratrooper, he has over 23 years of experience in leading U.S. soldiers worldwide. Col. Grossman retired from the Army in February 1998 and has since devoted himself to research, speaking, teaching, and writing. He has combined his experiences as a former Army Ranger and former West Point psychology professor and a professor of military science to become the founder of a new field of scientific endeavor, which has been termed “killology.” In this new field, he has made revolutionary new contributions to our un- derstanding of killing in war, the psychological costs of war, the root causes of the current “virus” of violent crimes that is raging around the world, and in the processes used to help victims of violence heal, in times of both peace and war. Col. Grossman is the author of On Killing, which was nominated for a Pulitzer and is is on the required reading list of the U.S. Marine Corps Commandant and the FBI Academy. He also coauthored Warrior Mindset and Stop Teaching Our Kids to Kill: A Call to Action Against TV, Movie and Video Game Violence. His book, On Combat has also been placed on the U.S. Marine Corps Commandant’s required reading list. On the Web, he maintains www. killology.com and www.WarriorSci.com.