Poll - are there any good prequels?

[jack]

This came up in the pub last night with the scifi society -- are there any good prequels, preferably scifi/fantasy? We thought of:

Children's books where the prequal is written second out of a series: Magician's Nephew, Charmed Life.
Series written out of order, such as Hornblower, Small Gods in TP.
Retrospective prequels: Asimov's robot stories became prequels to his foundation novels, though weren't at the time.

I decided that it's because prequels generally get written when an author (or their heirs) runs out of ideas, even more so than sequels, but if that's not the case they're by no means inherantly bad.

Can you think of any others?

Comments

[atreic.livejournal.com]

Fair enough. But I still don't feel it's a *prequil* as such. It doesn't explain something that has already been written about, which is what I think the essance of a prequil is... it just happens to be set in the same world at a slightly earlier time.