The common book size is 787 x 1092 mm, because the book size is related to the size of a large piece of paper. This piece of paper is folded in half to become two pieces at a time, which is called folio paper; After folding in half again, it becomes four, which is called four open; By analogy, there are names such as Octagonal and Sixteen Octagonal. These titles have been used to this day, as the general titles of book sizes in the publishing and printing industry.