The author interview: what is it for?

Do you read author interviews? And if so why? Is it partly to get to “know” the author? If so, then Writer’s Rooms does a good job with its photographs of writers studies (like that of Russell Hoban, above). Or do you hope for some insight you’d never get by reading their work? I was thinking about this when I did an author interview this week. I asked Bernardine Evaristo about her life and her novel Blonde Roots. Then I thought, isn’t all this “about the author” stuff just extra? If it was you, what would you hope to be asked? Or would you just want people to focus on the book?