Henry Ford improved assembly-line principles. Ford improved the assembly-line under the idea that it is more efficient for one person to do a single task over and over than it is for one person to put together an entire car. For instance, on the assembly line, a car would come by and Worker A would installs windshields. The car would then pass to Worker B who installs headlights and then to Worker C who adds the tires. This process is more efficient than Worker A, B, and C each putting together an entire car.
Ford is terrible by the way.