At the end of the 1950s, Formula 1 saw the transition from front-engine to mid-engine monopostos. One of the pioneers was John Cooper, who opted for an engine behind the driver early on. As a "garagist", however, he had to make many compromises, but his vehicles and especially the T51 from 1959 nevertheless showed the way. This contribution to the history of racing car technology explains the technology of the Cooper T51 from 1959 and shows it in many pictures.