The content of the CD's are good. The overview is a bit cursory and is not really in depth as I would have liked. The biggest problem is that the sound quality is terrible. I have to crank the volume to even be able to hear the discussion. If I am riding the train then forget about it; I can hear nothing. Great if you are sitting at home and listening in a quite space. Terrible if you are a commuter like I am and are trying to listen on the go.