Nearing The End Of A Novel

It is well written. It holds my interest. There are stories within the story. There are many characters and interesting description of places, people and things. The pocketbook version is about 636 pages. I have about 100 more pages to go to the end of the book. I have an idea how it will end but don't know for sure. I can't help but wonder how the author has the ability to write so many books. Many are similar but there is something distinctly different about each one. I guess that's where the imagination comes in. I wonder if it would help to make up an oral story and to then start writing it all down? Could be worth a shot! Where's the tape recorder?