In the age bracket of who buys John Grisham (usually older teens and adults), I think it's safe to say that John Grisham is at least almost as well known as JK Rowling. Just think of how many bestsellers Grisham has released...

So I don't think it's about being 'well known', because with JK she has a huge target with children and Grisham obviously doesn't, so you can't really compare the two, at least in my opinion.

Anyway, Grisham took it very well, and I shall continue reading both author's works quite happily. I must admit, though, I'm always much more excited about JK's new books than I am about Grisham's!