I have some problems with the lyrics to Paperback Writer

Don't get me wrong, I love the Beatles, and I think it's a nice, fun song... but have you ever listened to the words to that song? First off he says that the book he's writing is based on a novel by a man named Mier. How do you write a book based on a novel? My second problem is that he states that it's about a thousand pages, and if his reviewer likes the style he can make it longer. How many 1,000 page paperbacks have you ever read? No editor in his right mind is gonna tell him to make it longer. I think I had a couple other problems but I can't remember them right now.