Adding the artist to the art

With recent revelations about Munro and Gaiman there has been a lot of talk about separating the art from the artist.

For me, I think there are times when knowing about the author's biography and beliefs enhances their works and makes their works richer. For example, Kurt Vonnegut. He puts a lot of his personal history, experience, and beliefs into his characters. If you read a few of his works and have a wikipedia level of knowledge about him, you start to connect the dots and his characters just seem way more tragic and tortured than if you knew nothing going in. He's one of the few authors that can make me stop reading because I read a line that made me so profoundly sad that I have to sit with it for a moment. I don't feel that level of empathy for a fictional characters, only for real people.

What are some other works that are enhanced by adding the artist to their art? Should a work be judged by it's own merit and not be enhanced by any outside information?

Edited to add: I am talking about examples when adding the artist to the art makes the work better, but I am enjoying the discussion about separating the art from the artist.