Warning: Wikipedia contains spoilers
In Forward the Foundation, Isaac Asimov continues the chronicles of the life of Hari Seldon (begun in Prelude to Foundation), the man who laid the framework for the grandest project humanity has ever attempted.
Plot
The story takes place on Trantor, and picks up ten years after the events of Prelude to Foundation. It depicts how Hari developed his theory of Psychohistory from hypothetical concept to practical application in galactic events.
Beginning during the latter years of the reign of Emperor Cleon I, Hari's work inexorably brings him into the world of galactic politics, and takes him to the height of Imperial power as Cleon's first minister, after the mysterious disappearance of his previous first minister, Eto Demerzel (whom Hari knows as R. Daneel Olivaw. Hari becomes First minister to the emperor, but loses it ten years later after the Emperor is killed.
Gradually, Hari loses all those who are close to him. Hari's wife Dors is killed saving his life from an assassin (we find out that she is, in fact, a robot). His son Raych is killed in the Rebellion in Santanni, his daughter-in-law and grandson are missing and never found. Yugo Amaryl dies early, brought on by the strain of his work. Except for grand-daughter Wanda, Hari is alone. He eventually sends her off to start the second foundation.
The Galactic Empire's decline begins to accelerate. While at the same time, Hari finally begins to unravel the secrets of psychohistory and begin a grand plan that will come to be known as the Foundation.