Second Foundation is the third novel published of the Foundation series by Isaac Asimov, and the fifth in the in-universe chronology. It was first published in 1953 by Gnome Press.
Second Foundation consists of two previously published novellas originally published in appearing in Astounding Magazine (with different titles) between 1948 and 1950, making this the third volume in Asimov's Foundation series. Decades later, Asimov wrote two further sequel novels and two prequels. Later writers have added authorized tales to the series. More: en.wikipedia.org.