This is the best of the series since the first volume - it had been getting a little stale. And to be perfectly honest, there's still a bit of repetition here. These books do tend to follow a pattern, but this one breaks out of it, a little, to give a conclusion that folds in the Foundation books with Asimov's Robot series. I'd heard, via osmosis over the years I suppose, that Asimov's works tended to occupy the same universe so this wasn't entirely a surprise, but I wasn't expecting to enjoy the synthesis. That folding in seemed like it would be easy to over-work, like it would be something of a gimmick, and while it verges on that at times here this is still a thoughtful exploration of different possible futures, the mindsets behind those future, and the backstabbing that takes place in each of the main Foundation ideologies. (Plus a very entertaining treasure hunt for Earth, using the mythologies of its colonies.) It's a very political book, which is the sort of thing I find appealing, and it would be an unreserved 4 stars if the author could only have cut down on his need to exhaustively explain things, because this was a good 150 pages longer than it needed to be, I reckon.