Second Foundation
Second Foundation is the third novel of the Foundation series.
The term also describes the organization by that name which is the focus of the book. The organization's existence (and nothing more) had been revealed in Foundation, searched for in Foundation and Empire, and makes brief appearances in this novel. It would not be described in detail until Foundation's Edge.
Spoiler warning: Plot or ending details follow.
The Novel
It is written in two distinct parts.
Part I: Search By the Mule is about The Mule's search for the elusive Second Foundation, with the intent of destroying it. In the end, Terminus, "at the other end of the galaxy" (from the first Foundation, also at Terminus); because they realized that "a circle has no end", you start at one end and just continue until you hit the same point again. Thus, they declare the Second Foundation destroyed after finding the roughly 50 mentalic agents on Terminus and are content to forget the matter. Finally, in response to the question "Where is the Second Foundation?", the First Foundation had found an answer that fit. However, although this was the answer that fit, this was not the answer that was true. This would be revisited in Foundation's Edge.
The Organization
The Second Foundation was founded by Hari Seldon as a budding colony of mentalics, people with telepathic abilities, located at Star's End, a planet vaguely referred to by Seldon. They are governed by a council of the strongest telepaths, called the Speakers. The leader of the group is the First Speaker (a possible reference to the Roman title Princeps).
