Are all novels fictitious?

A novel doesn't have to be pure fictional. It can be based on facts. While fictionentails the writing of a story or book that is not true, non-fiction is fact base. There are novels that are based upon facts but that are literary works that are spurred by imagination and details added to a true story. One such novel based on facts is Truman Capote's book "In Cold Blood". Most novels are known for being fiction, however.

Even when nonfiction is used in a novel, it has a storyline and follows events and characters. A manual on how to do a specific thing would not be a novel, no matter how long it was and neither would a book about astronomy unless it was put into story form with characters and events.