Isaac Asimov wrote the original "Foundation Trilogy" back in the early 50s, and I (as a very young man) remember getting the omnibus volume as the bait for joining the Science Fiction Book Club: merely 10 cents, plus shipping and handling. Like most impressionable youths, I thought it was just swell.
Nowadays, I note, you can get the same books, albeit illustrated, and with an intro by Paul Krugman, from the Folio Society, and it will set you back a cool $140 (plus, it appears, $12.95 shipping and handling.)
[Krugman's intro is available as a PDF here, and it's mostly free of his dreadful politicizing, so if you're interested.]
So: about 30 years after the original books came out, the Good Doctor A wrote this in 1982: Foundation's Edge. And I was still a young enough man back then to get it from the good old Science Fiction Book Club. And now, 30 more years after its original publication, it's part of my Asimov-rereading project.
The book is set 120 years after the events of Second Foundation, about halfway into the Seldon Plan, the psychohistorical scheme to bring civilization back to the galaxy as quickly as possible after the predicted fall of the Galactic Empire. The Plan is going smoothly: the First Foundation thinks it has destroyed the Second Foundation; the Second Foundation, secure on the Last Planet Anyone Would Suspect, continues to oversee the Plan's steady unfolding.
In fact, the Plan is going way too smoothly. Each Foundation has a Brash Young Man (or, as another character puts it: "undiplomatic young jackass") that realizes this, to the shock and horror of the respective power structures. Something unknown is going on in the galaxy, and each jackass is sent on a mission to discover what that is.
Even after Asimov's decades-long hiatus from SF novel writing, his style is still there: almost all the pages consist of people talking to each other. Things happen, sure, but it's mostly conveyed via stilted dialog. And things are not what they seem, people not exactly who they seem to be. (And if you know that, the big plot twist is pretty easy to see coming.)
But still, it is a pretty tidy ending. And—do I need to say "Spoiler Alert" for a 30 year old book?—Asimov starts to tie together all his previous books into a coherent whole, something he never attempted in the 50s. (Ever wonder why there were no Three-Laws robots in the Foundation series? Find out!)