This is the third of Asimov's Foundation novels, and the last of the original Trilogy. After this he left the Foundation alone for many years. This volume picks up where the previous one left off. The Mule was thwarted when Bayta Darell killed Ebling Mis, thus preventing The Mule from learning the location of the Second Foundation. But The Mule could not be secure if the Second Foundation was out there, so he mounts a search, using whatever clues he can find. One of those clues was Star's End, and that leads him to a star system called Tazenda, which might be a corruption of Star's End. It looks deceptively rural and unassuming, but if a group is hiding itself it might do just that. The Mule goes there, but is met by someone from the Second Foundation, and it turns out this person also has unusual mental powers, strong enough to overcome The Mule. A little psychic surgery and the galaxy is safe.

But now the Foundation is aware of the Second Foundation, and that is causing problems. This knowledge is making them act in the wrong ways. Instead of relying on themselves, which Seldon's plan requires, they are now expecting the magical Second Foundation to bail them out of any problem. A group of Foundationers want to find and eliminate the Second Foundation, and they mount a search themselves. The grand-daughter of Bayta Darrell, Arkady Darrell, gets involved in things, and flees to Trantor in the company of a nice trader. In the end, the Foundationers are successfully convinced that they have found and eliminated the Second Foundation, but they haven't. Because it is not where they think it is. So Seldon's plan is safe - for now.

I now have this as part of a 7-book set of all of Asimov's Foundation novels in e-book form.