[Philippe D.]

Originally Posted by ZodWallop

Stephen R. Donaldson's Gap Cycle. The fact that this springs so quickly to mind tells you that it is exceedingly rare.

I read this quite a few years ago, but wasn't there an afterword in the first book (or a foreword in the second, or something like that) where he explained how he initially wrote the first book as a single story, and only understood why he wasn't satisfied with it when he committed to writing a whole series after it?