Henry Ford invents in 1908 the moving assembly line creating continuous flow as a production method
“ The thing is to keep everything in motion and take the work to the man and not the man to the work. This is the real principle of our production and conveyors are only one of many means to an end.”
In 1902 Sakichi Toyoda, founder of the Toyota group, invented an automated loom that stopped anytime a thread broke. As a result, quality defects significantly decreased and one operator was able to monitor several machines at one time.
Kiichiro Toyoda (studied in the US automobile manufacturing) convinced his father to have an automotive department in the Toyoda Automatic Loom Works. It will become Toyoda Motor Company Ltd in 1937.
During the Second World War, Taiichi Ono originated what has become known as the Toyota Production System TPS codified many of the principles which are the foundation of Lean.
James Womack, a professor at MIT, built upon the methodology of Toyota Production System and outlined a 5 step process for applying the principles of the Toyota Production System.
This 5 step process is outlined in the book Lean Thinking.