Even if you're not a huge fan of Paul Krugman, the trouble-making economist and New York Times columnist, you should check out his introduction to a new edition of Isaac Asimov's Foundation trilogy (PDF). He explains pretty succinctly just why these novels are great, and why they had such a huge impact on the young Krugman.
And then he talks about how the science of psychohistory means that every victory of the Foundation is predicted, in advance, by Hari Seldon. Which turns this into a "tale of prophecy foretold." Adds Krugman:
This unique plot structure creates an ironic resonance between the ‘Foundation' novels and a seemingly unrelated genre, what I'd call prophetic fantasy. These are novels - Robert Jordan's ‘Wheel of Time' cycle comes to mind - in which the protagonists have a mystical destiny, foreshadowed in visions and ancient writings, and the unfolding of the plot tells of their march toward that destiny. Actually, I'm a sucker for that kind of fiction, which makes for great escapism precisely because real life is nothing like that. The first half of the ‘Foundation' series manages, however, to have the structure of prophecy and destiny without the mysticism; it's all about the laws of psychohistory, you see, and Hari Seldon's prescience comes from his mathematics.