I read a comment recently that said the last 20% of a novel is the most difficult to complete. Considering that I'm currently struggling with just that (almost 20% exactly), I'm inclined to agree. Other people say that the end is their greatest part, though. That once they get on that exciting downhill slide, the words just pour out. I envy that.
I also got into a discussion this morning about how many books a writer generates in a set time period. I see authors out there who put out three and four books a year. On a writers' board I frequent (read: lurk on), one person says it takes them three months to write a book and then perhaps another nine months total on final revisions.
I have worked on this book for probably three years now. Granted, I haven't been able to devote all the time to it I would have liked, but I still know that I couldn't generate this in three months. A happier goal for me would be to take a year to write a book, then maybe a month for the first Big Revision. Sometimes, I wonder if I'm doing this wrong.