With dimensions of approximately 6" x 9" (150mm x 230mm), the Octavo is one of the most ubiquitous book formats in modern publishing. Its compact size with a surface area around 54 square inches or 348 square cm has made it ideal for paperback books and mass market printing. Sometimes known as Mass Market Paperback or just Paperback, Octavos became widely popular in the 20th century for publishing inexpensive fiction. The size allowed convenient portability with enough area for clear text across pages. Originating from early modern bookbinding, Octavo gets its name from eight leaves of paper being folded into one signatures. Especially common for paperback novels and small nonfiction in North America, the Octavo's success stems from efficient printing and how well it fits in a jacket pocket. The 6" x 9" size can comfortably fit around 300-400 pages printed on both sides. Easy to hold and stow away, the Octavo helped push paperback publishing into the mainstream.