Book size

For example, a quarto (from Latin quartō, ablative form of quartus, fourth[3]) historically was a book printed on sheets of paper folded in half twice, with the first fold at right angles to the second, to produce 4 leaves (or 8 pages), each leaf one fourth the size of the original sheet printed – note that a leaf refers to the single piece of paper, whereas a page is one side of a leaf.

The binder would sew the gatherings (sometimes also called signatures) through their inner hinges and attached to cords in the spine to form the book block.

The vast majority of books were printed in the folio, quarto, octavo or duodecimo formats.

[5]: 30–31  For example, three two-leaf printed sheets might be inserted in a fourth, producing gatherings of eight leaves or sixteen pages each.

[5]: 28 In determining the format of a book, bibliographers will study the number of leaves in a gathering, their proportion and sizes and also the arrangement of the chain lines and watermarks in the paper.

For example, a modern novel may consist of gatherings of sixteen leaves, but may actually have been printed with sixty-four pages on each side of a very large sheet of paper.

Modern books are commonly called folio, quarto and octavo based simply on their size rather than the format in which they were actually produced, if that can even be determined.

Scholarly bibliographers may describe such books based on the number of leaves in each gathering (eight leaves per gathering forming an octavo), even where the actual number of pages printed on the original sheet is unknown[4]: 80–81  or may reject the use of these terms for modern books entirely.

During the hand press period, full sheets of printing paper were manufactured in a great variety of sizes which were given a number of names, such as pot, demy, foolscap, crown, etc.

For example, a typical octavo printed in Italy or France in the 16th century is roughly the size of a modern mass market paperback book, but an English 18th-century octavo is noticeably larger, more like a modern trade paperback or hardcover novel[citation needed].

The words before octavo signify the traditional names for unfolded paper sheet sizes.

In book construction, Japan uses a mixture of ISO A-series, JIS B-series, and several traditional Japanese paper sizes.

A- and B-series signatures are folded from a sheet slightly larger than ISO A1 and JIS B1, respectively, then trimmed to size.

Comparison of some book sizes based on American Library Association . [ 1 ]
Traditional book sizes/formats used in English-speaking countries. Based on the 19-by-24-inch or 482.5-by-609.5-millimetre printing paper size, which equals two folio leaves, four quarto leaves, eight octavo leaves, etc. For comparison, common American letter size is shown in green.
An extremely large book rests on a table, with its front cover and a small portion of its pages flipped open to the left. A man facing away from the camera stands in front of the flipped part. On the wall above the book is a sign saying "LARGEST BOOK IN THE WORLD - VISITORS' REGISTER FOR CALIFORNIA BUILDING - Alaska–Yukon–Pacific Exposition […]". On a table in the background and to the right of the large book is another table on which many small stacks of normal-sized books are visible.
The supposed largest book in the world, as of 1909. It was the visitors' register for the California Building at the Alaska–Yukon–Pacific Exposition in Seattle . Some normal-sized books are on the table at right.