Originally published in 1943 "Combato" was created by Bill Underwood during wartime for use in close quarter combat. This unique system is a martial art and self-defense system used in the armed forces, law enforcement, and for personal development. "Combato" techniques can be learned by anyone and are not based on physical strength or athletic ability. The average person will benefit from the practice by learning practical self-defense skills but also increase their self-confidence and well-being. A great addition to any martial arts library.

Combato had its beginning in the Liverpool theatres with jujutsu demonstrations by travelling Japanese wrestlers, Yukio Tani and Taro Miyake. As a boy, Underwood idolized these experts, and rapidly established himself as a prodigy.

Underwood was frequently requested by American and Canadian Law Enforcement Agencies to teach his Combato system during World War II

After the war had ended he refused Underwood modified the system to remove its lethal applications and instead focus on the Law Enforcement applications of self-defence, compliance and control tactics and called it "Defendo."

Between 1980 and 1981 Underwood appeared four times on The Tonight Show Starring Johnny Carson. He also appeared at that time on all of Hollywood's major talk shows including Real People, That's Incredible, and Merv Griffin. In 1980 a short documentary film about Underwood's life and work, entitled Don't Mess With Bill was nominated for an Oscar at the 53rd Academy Awards in 1981.