Who is Warren Monfort from Fast Food Nation and what is their importance?

Warren Monfort is a small rancher in Greeley, Monfort discovered that, by buying cheap grain from his neighbors, he could fatten up his cattle at will and therefore control when he sold them. He also discovered that grain-fed beef was fattier and more tender, needing no aging time. His "experiment" eventually revolutionized the entire beef processing industry. He opened the first beef processing plant in Greeley, Colorado, using skilled union processors and packers. Eventually consumed by greed, Monfort closed the plant and re-opened it as a non-union facility. Eventually, he sold the Greeley plant to ConAgra.