William E. Fairbairn was one of the most influential instructors of the last hundred years. He began by studying Japanese and Chinese martial arts whilst serving in the Shanghai police. His early attempts to develop a fighting style of his own, led to the publication of his book Defendu in 1926.
Later, with the outbreak of WWII, Fairbairn was encouraged to adapt his self-defence system for hand to hand combat training. Working with the British Commandos and U.S. Rangers, he developed his Close Quarters Combat (CQC) program.
Fairbairn described himself as teaching ‘gutter-fighting’ where there were no rules but ‘kill or be killed’. Yet his books describe techniques in scientific detail. They collate data, map weapons and targets, and chart their effects. He even took rudimentary psychology into account in the development of his tactics.
You can see Fairbairn’s methodology still in use today in this USMC Close Combat Manual.