An unpublished book refers to a book that hasn't been printed or made available for people to read or buy yet. It is a book that has not been released to the public. Full definition
True, when seeking a traditional publishing book deal or agent representation for an as yet unpublished book, the questions about current sales are irrelevant. (toughnickel.com)
He / she wrote a few unpublished books at a young age. (bookworks.com)
Recently I had the opportunity to read an as yet unpublished book on the Mormons, The Evolution of Mormonism, by Mark Leone. (religion-online.org)