In Isaac Asimov's Foundation, a Foundationer was a member of the intellectual elite who would bring about the Second Galactic Empire. Members of the Foundation (a.k.a the First Foundation lived on Terminus and were masters of the physical sciences. Members of the Second Foundation were masters of the mental sciences.

Warning: spoilers!!!

Although the Second Foundation (which remained on Trantor after the fall of the First Galactic Empire) believed themselves to be the true Masters of the Universe, they too were subject to the subtle, external control of the robot R. Daneel Olivaw.