Books/Authors in the Literary Conversations series

Do you think a book in the Literary Conversations series should have as its author the editor of the book or the author being interviewed or both?

1) Author: http://www.librarything.com/work/2490699
2) Editor: http://www.librarything.com/work/6648890
3) Both: http://www.librarything.com/work/4750875

Given that the author is the one being interviewed, and that there would be no book without his contribution, I wonder if the author should be the Primary Author or Main Author/All Editons, with the editor optional.

On a related note, books of letters.

I would think books of correspondence would use the correspondents as Main authors, with editor Secondary Author or optional.

What do you think about this:

http://www.librarything.com/work/536004

Moved subjects of threads to Talk About Library Thing.