I love Piers Anthony’s books, but I really don’t see them making very good screen adaptions. On a Pale Horse is a good book, but it only really shines when you read the entire series. It’s the same thing with the Apprentice Adept series; good, but you’ve got to read all of them for the whole story. Plus, there’s just too much plot and underage sex to be chopped for a good screen adaption. Imho, ymmv.