Tor has a piece up about Theodore Krulik's biography of Roger Zelazny.
I came to the biography after I had already read the majority of Zelazny's work. I think my problem with it was that I had already read the biographical segments from the Collected Stories, and the Collected Stories did the same thing as Krulik's biography, but in a more engaging fashion. In addition, since those segments were written later, they provide a more comprehensive picture. Had I come to it earlier, I might have come to a different opinion.