Printed Paperback, or soft cover book or soft back describe and refer to a book by the nature of its binding. The covers of such paperback books are usually made of paper or cardboard, and are usually held together with glue rather than stitches or staples. Paperback print editions of books are issued when a company decides to release a book in a low cost format. Paperbound can be the preferred medium when a book is not expected to be a major seller, or in other situations where the publisher wishes to release a book without putting forth a large investment. Many modern books, especially genre fiction, are first editions in paperback. Only the best-selling books, such as Bible paperback or Harry potter paperback, can maintain sales in hardcover sufficiently to delay a paperback edition for longer than a year.