It's been many years since I cracked open a copy of Foundation, let alone read through all of the books. However, it's been proving to be a great deal of fun. The stories don't diminish, even as my knowledge of science make the deficiencies in science and technology that Asimov lived in show through. Still, the stories remain strong.
What's interesting is that I never consciously realized that the Foundation trilogy - vast science fiction epic though it is - has exactly zero androids in it. Therefore, there are no cases of the Three Laws of Robotics, either. This is - to me - strange, since Asimov is known for the Three Laws as well as the Foundation.
Poking around on Wikipedia, I learned that in the fictional chronology, between the period in which "Robots" series of books and short stories take place and the time of the Foundation series, there was a diminishment of the number of robots. Indeed, in Caves of Steel the number of robots were already in serious decline as humans moved to get rid of them, even as the Three Laws protected them from the robots.
Another thing that's interesting is how uncannily similar Asimov's "psychohistory" is to certain economic and quantitative social sciences. I don't know if these social sciences were developed to such an extent in Asimov's time, but whenever we think about "market projections" and the like, it's almost like an analogue of psychohistory. Furthermore, the kinds of projections that are made by Nate Silver (over at 538) is itself a kind of "psychohistory".
All kinda cool, especially since these thing were in their infancy back in 1942 (when the first short story of the Foundation series was published).