Terry Pratchett, UK author with ton of best sellers here and abroad. Ostensibly most famous for his Discworld series of books but also author of The Bromeliad trilogy, the Johnny Maxwell books and more. He also did a stand alone book with Neil Gaiman called Good Omens which is where a lot of kids started to notice him in the states. His work often inspires spin-off collaborations with fans such as full color maps of the Discworld or conversions of his books to stage plays.
Pratchett's books are light hearted in tone but not always in subject matter. To paraphrase a recent South Park he is, "A genius literary motherfucking wordsmith." He is one of those people for whom it makes little sense, to me, that he isn't more famous than he is. Hopefully there are some fans on the board?
As a snippet example, here is one of my favorite parts from an early work. From the Terry Pratchett book "Small Gods." A discussion between the (perhaps temporarily) omnimpotent god "Om" and his, formerly singular, follower and prophet "Brutha." It is structured similar to bible verse as it is quoted from (into?) the "Book of Om" as the founding of the new "omnianism" with Brutha in quotes and Om speaking in capitals.