Got all three when they came out, still have them. I got at least one in mono, might have been two, have to look and see which way, but I do recall not all 3 in stereo. They were my introduction to Otis Rush, among others. I was a freshman in college and they had some good blues LPs in the college bookstore.This is a good, 3-LP sampler that was released during the "blues revival" that started during the mid-1960s. There are four sides by Johnny Shines on it as well some killer stuff by several other great Chicago players:
If you stay tuned to the link after the first song finishes, it will cycle through all three LPs. If you go to YouTube to watch/listen instead of staying here (click on "Cotton Crop Blues"), you can pick and choose which ones to listen to.