Quarto

A quarto (from Latin quārtō, ablative form of quārtus, fourth)[2] is a book or pamphlet made up of one or more full sheets of paper on which eight pages of text were printed, which were then folded two times to produce four leaves.

The earliest known one is a fragment of a medieval poem called the Sibyllenbuch, believed to have been printed by Gutenberg in 1452–53.

Beginning in the mid-nineteenth century, technology permitted the manufacture of large sheets or rolls of paper on which books were printed, many text pages at a time.

As a result, it may be impossible to determine the actual format (i.e., number of leaves formed from each sheet fed into a press).

During the Elizabethan era and through the mid-seventeenth century, plays and poems were commonly printed as separate works in quarto format.

Bibliographer Alfred W. Pollard named those editions bad quartos, and it is speculated that they may have been produced not from manuscript texts, but from actors who had memorized their lines.