When people talk about pocketbooks, they’re usually referring to books that are known as paperbacks, or soft cover books. Usually this type of book has a cover which uses paperboard or paper, and the thing that keeps the pages together is glue, instead of staples or stitches.

Books that were cheap and which used paper for bounding can be traced even to the 19^th century and the formats which they used were varied, ranging from dime novels, to yellowbacks, pamphlets or airport novels. Usually, a paperback is either a trade paperback or a mass market paperback. The other type of book that is not considered a pocket book, is the hard cover one, which costs more but also lasts for a longer period of time.

The book editions which are launched in paperback appear usually because the company wants to launch a book that doesn’t cost much. They use cheaper paper, soft cover and stitched bindings, to reduce the cost and sell it cheaper, at least when you compare it to the cost of a hard cover book.

The pocket book format is usually used when you’re launching a book which will probably not sell extremely well, or whenever you want to launch a book without investing too much money in it. This happens for reprints of books that are older or for many of the novels.

Usually a publisher needs to balance between the hardcover books, which sell for more money per book, versus the pocket books, which sell for a smaller profit but are sold in larger numbers. Many of the fiction books launched these days are sold directly in paperback form, while best sellers might sell only in hardcover in the beginning, with the paperback launching one year later, after the sales of the expensive versions began to drop.