" Ask a book publisher how many copies a book has sold, and he or she, presuming you’re not the author, will probably try to remember the size of the first printing, then double it. If you’re the author, the publisher will try to remember the number of copies that were shipped and cut that in half in order to avoid encouraging you to expect a big royalty check. "

― Michael Korda , Making the List: A Cultural History of the American Bestseller, 1900-1999