The first psychohistorian, also the First Minister of the Galactic Empire under Cleon I, as told by Isaac Asimov's Foundation series.

Seldon first proves psychohistory is feasible when he is rather young, but it takes him the rest of his life to fully develop the science. He begins at Streeling University on Trantor, where the Hari Seldon Psychohistory Project is eventually begun. Rather than try to study the twenty-five million worlds of the Galactic Empire, he studies the various sectors of Trantor itself to establish the laws of psychohistory.

In order to shorten a predicted dark age, Seldon sets up two Foundations: the Encyclopedia Foundation located on Terminus, and the more secretive Second Foundation at Star's End.