We are constantly told the first page of our novel is vital in grabbing the attention of a reader. Ray Rhamey in his blog Flogging the Quill analyses what works and what doesn't for readers who send him their first chapter. He often suggests that the writer is starting in the wrong place, and gets his readers to vote on an alternative beginning. My friend Alan Hutcheson told me to start Trav Zander a couple of pages in, and everyone preferred his first line: "I wish to acquire a dragon."
I think endings are as important as beginnings - after all, it's the last thing your reader reads, and you want her to put the book down with a satisfied sigh, not hurl it across the room. Jane Austen knew what happened to her characters after the novel ended, and would sometimes disclose a tantalizing detail in her letters, for example that Jane Fairfax died early. But she doesn't tell the reader that.
Do all novelists know what happens after the last page? I do. I know what Trav and Isolda do next, and who Caz marries. I'm not prepared to reveal anything after THE END, though, even supposing anyone was interested, because the point at which your story stops is important. With Jane Austen, it was invariably the marriage of hero and heroine, and a couple getting together remains a popular happy ending to this day. After the ceremony, they subside into domesticity, children and contentment - and who wants to read about that? Poor Jo in Jo's Boys, married to a dreary middle-aged German and fostering lots of children makes one grind one's teeth, after her feisty start in Little Women.
Much as I like a happy ending, I prefer to leave the ends of my books a little open, so that the reader is left speculating on what will happen next, rather than tying up every loose end too neatly. Just as long as they don't get it wrong...