Distributed by chapmen, or itinerant tradesmen, who travelled to rural localities selling wares at fairs, town markets, and auctions, chapbooks were popularized in Elizabethan England and were in use until the late 19th century, when the growth of the popular press and increased opportunities for children's education ended their demand.
Chapbook derives its name from the Middle English term for trade, ceap. The ephemeral books were printed on a single sheet of inexpensively manufactured paper that was folded 4, 8, 12, or 16 times in order to produce small books of 8, 16, 24, or 32 pages. Chapbooks were often sold uncut and unbound, so readers would cut the pages and stitch or pin them together to create the book. Generally, the books feature one or more woodcut illustration, which may or may not relate to the text, and which are occasionnaly hand colored. Most important, the chapbooks are small and lightweight, making the burden of the chapmen light as they traveled from town to town.
Source: The Columbia Encyclopedia. New York: Columbia University Press, 2008. s.v. "chapbook," http://www.credoreference.com/entry/columency/chapbook (accessed April 09, 2010).