Robert Gilmour LeTourneau, the inventor of earthmoving machines, secured nearly 300 patents over the course of his life. During World War II, about 70 percent of the earthmovers and engineering vehicles were his machines that were invaluable to the Allied war effort. With outstanding photography, this overview of 90-years-plus of manufacturing features the company's earliest earthmoving equipment introductions in 1921, all the way up to today's ultra-large mining equipment introductions. This companion book to the three previous publications - R.G. LeTourneau Heavy Equipment: The Mechanical Drive Era 1921-1953, R.G. LeTourneau Heavy Equipment Photo Gallery: The Electric-Drive Era (1953-1970), and Modern LeTourneau Earthmoving Equipment since 1968 - includes updated information and all new images of the LeTourneau enterprise.