From the North Dakota beet fields to California's National Forest campgrounds to Amazon's Texas CamperForce program, employers have discovered a new low-cost labor pool: transient older Americans. With Social security coming up short, these invisible casualties of the Great Recession have taken to the road by the tens of thousands, forming a growing community of migrant laborers dubbed "workampers." In a secondhand vehicle christened "Van Halen," Bruder hits the road to tell an eye-opening tale of the American economy's dark underbelly. -- Page 4 of cover.