Thomas Wade "Tom" Landry (September 11, 1924 – February 12, 2000) was an American football player and coach. He is ranked as one of the greatest and most innovative coaches in National Football League (NFL) history, creating many new formations and methods. He invented the now popular 4–3 defense, and the "flex defense" system made famous by the "Doomsday Defense" squads he created during his 29-year tenure with the Dallas Cowboys.