Speaking of "Slavery by Another Name," I've been re-reading (listening, actually) "Grapes of Wrath" It's been a long time since I read it for the first time, but I've made references to it for years. (e.g., seeing somebody at a campground that "looks like a bunch of Joads", or somebody on the freeway in an old truck piled to the to with junky stuff, "a Joadmobile.") It was interesting a couple of years ago when we spent some time around Monterrey, went to Cannery Row, went to Steinbeck's house in Salinas, and saw plenty of people working in fields who could be the fictional Joad's descendants.
But the description of how the big farm owners used, abused, and controlled the workers clearly showed a system of involuntary servitude, differing from "slavery" only in that people weren't actually bought and sold. The farm owners would solicit far more people than they needed, and then offer work at a lower rate to the most desperate/hungry, then lower the rate for all. Farms were fairly specialised, so when a harvest was over, there was no more work and the workers were chased off. Incidentally, two of the reasons for that were (1) to keep the workers from staying in one place long enough to be eligible to vote and (2) to limit their ability to organize and/or form community bonds. The owners had the police in their pockets, too, so if a worker was thought be be any kind of trouble, he'd generally be killed or severely beaten.
The evil cycle generally ended with the start of WWII, when many of the transients went into the military and many other non-agricultural jobs became available.
One of the migrant camps the Joads stayed in was the "Weedpatch Camp", slightly south of Bakersfield. Weedpatch is real, and although the facilities are much better than in 1939, it still provides housing for migrant workers.
Real "Joads" from 1939
