I want to enhance Zypher's answer.
Let's point out the differences between a novel and a book:
A novel is a book-length work of fiction. Just being fictional and bound isn't enough -- collections of short stories, novellas, and other fictional texts can be bound, but they don't thereby become a novel.
A book, by contrast, is a volume of fictional or non-fictional work. Although these are often bound, again, binding isn't essential. For example, books can be electronic with scanned images. The lack of binding doesn't mean that it isn't a book. Additionally, a book -- in common usage -- tends to have a copyright and be the product of a publisher. One could debate this aspect (e.g., is an unpublished diary a book?)
In short, a novel is usually a book, but a book isn't necessarily a novel. The terms aren't interchangeable. Just remember that novel normally refers only to works of fiction. If the book isn't fiction, it isn't a nove
See : Difference between book and novel
So i think we need two different tags.
