I'm not a regular Hellboy fan, though I loved the movie, but when I read that Tom Piccirilli had based a character on Manly Wade Wellman's Silver John (I hate it when they call him hillbilly; the movie based on the character was called The Legend of Hillbilly John. What a travesty that was!), I had to get it. I enjoyed the book, though at first I wasn't sure where the author was going, but it had a satisfying ending--with a fantastic, imaginative trip on the way; and I liked Hellboy and the other characters. Well drawn, and Hellboy was Hellboy. This is not a graphic novel, btw; and there are horrific scenes.
I got Nim's Island, the book, after seeing the movie. (One review called it far-fetched; it could have said unbelievable.) I usually read the book after seeing a movie if I haven't read it already. The book is better and way different from the movie!