Lt. Col. Dave Grossman (Ret.) is the author of the books On Killing (half-million sold, 1,000+ reviews 4.5 stars on Amazon, USMC Commandant's "required reading list"), On Combat (also USMC list), and many others.
He is a retired West Point psychology professor, U.S. Army Ranger, and paratrooper who holds 6 gun patents and is the owner of Sheepdog Knife & Gun. He was inducted into the USA Martial Arts Hall of Fame for his accomplishments as a black belt in Hojutsu (martial art of the firearm).
After retiring from the Army in '97, he has been on the road over 200 days a year for over 20 years, training police in all 50 states, US federal agencies, US military, and many foreign nations.
**NEW** On Spiritual Combat - https://www.amazon.ca/Spiritual-Combat-Missions-Victorious-Warfare/dp/B087YG8WVL/