I think this is alright as well. Many things do become "common knowledge". The book probably didn't come up with the original idea/argument anyway. Of course t

I think this is alright as well. Many things do become "common knowledge". The book probably didn't come up with the original idea/argument anyway. Of course tangential to the citing of novel ideas is the citing of material that helps explain your work. I think it's certainly a good idea to cite a source of common knowledge if that source does an especially good job of presenting that knowledge. As with all things, this is a judgment call. Just try to be honest...