Continuing my trek through Isaac Asimov's science fiction novels. In this case, re-reading one after (approximately) 45 or so years. It's the third installment in what was (back then) Asimov's "Foundation Trilogy." Like the others, it was originally published in pieces in John W. Campbell's old magazine Astounding Science Fiction.
The First and Second Foundations were established at the beginning of the series by "psychohistorian" Hari Seldon. Their purpose was to minimize the chaotic period following the collapse of the Galactic Empire (accurately) predicted by Seldon. The First Foundation was set up on the periphery of the galaxy, devoted to physical science. In contrast, the Second Foundation operated in secrecy, at a location Seldon only hinted at, and specialized in matters psychological.
In this book, the Second Foundation is sought. First by the "Mule", a mutant with enhanced mental powers who sees it as his only obstacle to galactic domination. Then, in the second part, the First Foundation becomes concerned about the Second, when it's discovered that key people have been subject to their mind-altering manipulations.
As always with Asimov's books, the talk/action ratio is very high. There are a lot of twists, people who are not as they seem, double-crosses, and fake-outs. The beginning of the second part of the book, where the teenage heroine Arkady Darell meets Pelleas Anthor, is very, very funny.