| Third book in the original Foundation series by Isaac Asimov. Copyright 1953.
It contains two stories The Mule's search for the Second Foundation and the First Foundation's search for the Second Foundation. Hari Seldon said there would be two Foundations, but no one knows the location of the second or are even sure it exists. But every now and then somebody will try to find it. First the Mule begins to believe in it and searchs for it, later the First Foundation makes an attempt also. | 
