Quote Originally Posted by KittenEV View Post
My book is written in third person. But the main character finds a journal that has a bit exposition in it. Would copying a blurb from that journal and having that be the back cover blurb be okay? It's from the perceptive of a minor character and written in first person so i'm not sure.
No one can stop you doing anything and there are no rules. But the majority of quotes from a book don't really work outside of the context of the book. You need something that makes it very clear what the book is about. You also want to be specific about it. If you give a generic description that could apply to the whole genre, that doesn't help (this is things like "An epic battle between good and evil!" which describes far too many books to be useful).

If you go for a slightly longer one for your main description, you will also want a short one paragraph version. Some places want the shorter version. These days, I lean towards trying to make the one paragraph version the main version, but my first novel has a longer one as well.