The Necronomicon is a fictional creation. Despite some claims, there is no evidence to suggest it is a real spell book. It was made popular in horror literature, particularly by H.P. Lovecraft. So, it is fiction.
Well,'spell fiction' could mean to write or create fictional stories in a very captivating or magical way. It might imply using words to 'cast a spell' on the reader, drawing them into the fictional world you're creating.
If the Necronomicon spell book was not fiction, it would open up a whole new realm of study and danger. There would be ethical questions about using its spells, and the power dynamics it would introduce into society would be chaotic. But, as of now, it remains firmly in the realm of fiction. It was designed to tell spooky stories, not to be a real - world manual for magic. There is no evidence to suggest it has any basis in reality, and most likely it never will.
The proper spelling is 'non-fiction'. You just put 'non' and 'fiction' together with a hyphen. It's used to describe works that are based on real events or facts rather than imagination.