Now that I've read, y'know, every Discworld book ever written, I'm now limited by reality and Terry Pratchett's writing schedule to feed my urge. Fortunately, Pratchett has always been a fairly prolific writer, so the process is nowhere near as painful as, say, waiting for the next entry in A Song of Ice and Fire.
That said, I almost didn't pick up Unseen Academicals. I have no idea why, but for some reason I hadn't realized that it was a Discworld book. Maybe I had confused it with A Hatful of Sky or another of his juvenile books. I eventually realized my error, and felt pretty silly when I did - after all, Unseen University appears in virtually every Discworld book in one way or another, and Unseen Academicals was a pretty obvious reference to UU.
So, where does the book fit on the famous Reading Chart? Personally, I'd place it under the Industrial Revolution thread. It doesn't continue the latest adventures of Moist, but it completely fits in with the overall thrust of these books, which are all about taking modern concepts and incongruously transplanting them to a fantasy setting. In this case, that concept is organized sporting leagues. Psychology also makes a brief appearance, as do glamour fashion magazines and play-by-play commentary.
I must say, I was a little surprised by the presence of soccer (er, football) in the book. It works, but c'mon, sports and fantasy have to be about as far as you can get from each other. Somehow, I have the feeling that few of the readers of this book have great sporting experiences from their childhoods; they're far more likely to sympathize with Ponder Stibbons' memories of the kid who was picked last for a team. As always, though, Pratchett makes it work. You get to see the history of the sport in this alternate universe, see how it affects the day-to-day life within A-M, how it affects the passions of peoples' lives, why Vetinari cares about it, how he changes it, how sports can be good or bad... the most compelling part is the idea of The Shove, the sort of mass mind that takes over the throng of passionate spectators. It's something I recognize from my own experiences any time I join thousands of other strangers to watch a competition.
The plot is pretty sprawling (more on that later) and fun. There's a fairly small cast of main characters, all of whom would be nameless servants in other Discworld books. One is a cook who is the head of the Night Kitchen at UU; another, her assistant, is a beautiful but vapid assistant cook; the final two are candle dribblers, who are responsible for dribbling wax so wizards can use arcane candles which appear appropriately aged. The characters are well-sketched and likeable. The most compelling is Nutt, one of the dribblers, a "goblin" from Uberwald who has arrived in Ankh-Morpork under mysterious circumstances. Nutt is, to put it bluntly, much better than everyone around him. He is more thoughtful, more talented, stronger, patient, and determined. Due to his race, he needs to constantly try harder than everyone else and constantly prove his "worth." It's touching, and also a little sad, to realize how much effort he must expend just to achieve what others take for granted.
Besides the main characters, many of the old favorites return. Lord Vetinari has a surprisingly large role in the book, and we get to see far more unguarded moments of him than usual, including a great sequence where he purposely and coldly gets drunk. Of course, Drumknott is present as well. All the wizards are present. I was surprised and delighted when, about halfway through the book, Rincewind puts in an appearance - running away, of course. But he sticks around, and it's fun to see him staying put in the University for once. CMOT Dibbler and Sam Vimes put in nice little cameos. All in all, it's a great return to A-M.
Now, about that plot - like I said, it's quite sprawling. The book as a whole feels really loose. There are lots of scenes that start out being about one thing, then one of the characters will sort of drift into another conversation and pick up another plot thread, then drift back to the first plot again. The pacing as a whole is weirdly languid. At one point Nutt runs away from A-M, and the others go to chase after him; they have plenty of time for comic goings-on while they pursue him, and when they catch up, he doesn't resist at all about going back again. The whole incident... well, I guess it works, but it just doesn't feel nearly as dramatic as it could have been. Other side plots, like micromail (it doesn't chafe!) seem really interesting at first, but sort of peter out without a satisfying conclusion.
I have a confession to make: I found myself thinking a lot about Pratchett's Alzheimer's while reading this. It's pretty inevitable; obviously something like that would affect a person's writing. The good news is that the book is still really good. The complicated news is that it definitely feels different from his earlier books. Not totally different - in particular, the old characters do feel like the same people (or orangutans), and the sense of humor is very much intact. But the book as a whole reads much more loosely and casually than I'm used to. Some people might prefer it to the old style, others will be turned off.
In any case. It's fully enjoyable and well worth pulling out. It isn't quite as good (for me, at least) as a Vimes novel, but it's an A-M novel, and that's the next best thing. It's funny, thought-provoking, interesting satire. Just my cup of tea.