Publishers are increasingly ditching nonfiction paperback books, much to the chagrin of authors.

For years, the standard model of book sales has been for publishers to open with a more expensive hardcover, followed by a wave of cheaper paperbacks months later. However, the growing popularity of e-books and audiobooks, a near monopoly by a few book publishers, and changing reader habits have led to a drastic change in this model over the past six years, with paperbacks becoming more and more rare, the Wall Street Journal reported.