I might not go so far as calling him a genius, but I do love is humor. I'm in the process of reading Wintersmith, and love it almost as much as I loved the other novels about Tiffany, and I think the difference is really just that I read the others when I was younger and still part of the target demographic of his YA novels XD I've read The Colour of Magic as well, but from what I've heard of his subsequent Discworld novels, the first is not is best. Still good, though.