[TheDeadlyShoe]

Short version:

There was a galactic empire centered around the city-planet of Trantor. A man named Hari Seldon and his assistants developed 'psychohistory', a science that could accurately predict the future of human societies. The Empire was collapsing, and psychohistory showed that it was inevitable. The powers that be didn't like this... He contrived to start a Foundation on a distant planet with no natural resources that would shorten the predicted galactic Dark Ages tenfold. The foundation books chronicle Seldon's struggle and the (predicted) struggles of the Foundation, whose supposed purpose was to create a gigantic encylopedia.