Professor John J O'Brien was a former Inspector and Superintendent of Police in Nagasaki Japan, and is credited as the man who brought Jiu Jitsu to America in 1902. He was one of the first foreigners to receive an instructor diploma from the Japanese government, and was the Jiu Jitsu teacher of President Theodore Roosevelt and members of his cabinet teaching classes at the White House. In this classic text on Japanese Jiu Jitsu, Prof. O'Brien presents the secrets of this system of physical training and self defense. Over 25 self defense techniques are illustrated and described in detail.