trade paper back

A trade paperback (TPB, sometimes referred to as a trade paper edition) can refer to any book that is bound with a heavy paper cover that is generally cheaper than a hardcover but more expensive than a mass market paperback.
Trade paperbacks were once used primarily for special editions, but for many literary titles trade paperbacks have now replaced regular paperbacks as the format for a book's subsequent release once its hardcover edition has been discontinued. Generally, regular pocket-sized paperbacks are now used only for popular and genre fiction titles.
For new writers publishing their first works, a trade paperback may even be the sole format of a book's release.
Dimensions of a standard trade paperback are 198 mm × 129 mm (8" × 5¼").
In the genre of comic books, trade paperbacks are usually used to reprint several issues of a comic series, usually an important storyline or the entire series itself. Graphic novels are also usually found in trade paperback form.