Where do Agatha Christie, Dickens, etc. rate, if the Bible is the world's best-selling work of fiction?

Apparently they are not as highly rated. The Bible does contain fiction, but that does not mean it is a work of fiction. It is a Spiritual book which contains spiritual truths. Maybe you should read it, especially the part about Jesus... who He is and what He has done. There is a reason why they call it the greatest story ever told.