How can you tell a novel from a book?

It is usually quite obvious whether a book is fiction or non-fiction. Books of fiction tell stories, books of non-fiction present factual information. Now and then there are books which might fool you. For example, Philip Jose Farmer wrote two fictitious biographies, one of Tarzan and one of Doc Savage, which are presented as if they are biographies of real people. This was an amusing joke that Farmer was making. But if you read the books you should be able to tell that the events described by Farmer could not have really happened.