How important is the author to their work?
I've had a bad case of author hero-worship before. Several bad cases, actually, although whether or not it was actually "bad", as in "bad for me", is really a matter of opinion.
What it can be is painful when you realise your idol has feet o' clay. Take
Orson Scott Card, for example. Love the man as an author. Have even met him quite a few times in person, and he is a nice guy. He has some views that I can really respect...and then he has other views where I think he is totally out-to-lunch.
Take also
Teresa Nielsen Hayden. At an earlier point in my life, I would have disagreed with her vociferously on many things but now there are many things that I can really respect.
Both Teresa and Orson have a handful of things in common with me which make it immediately easier for me to relate to them on some things: we were all raised Mormon, for example, (albeit in different states and eras) and whether or not we still believe or don't believe the tenets of that religion, that background certainly has strong influence on how we write and perhaps more importantly, what we choose to write about. While knowing that background doesn't make a difference to the casual reader, to someone who shares that background, that's kind of like lighting a flare, saying, "Look, people like you." Thus I think it's easier for me to annoint them with hero-hood, and harder to separate the work from the person.
I don't think it's necessary to know about the author to idolise them or to enjoy their work (and in fact, it's usually EASIER to idolise people when you don't know them). But knowing more about the author undoubtedly will reveal unexpected facets of their work.