Print on demand or publish on demand (POD) is a printing technology in which a copy is not created until after an order is received. Using traditional printing technology, such as linocut, Gutenberg letter press or offset printing, it is quite complicated, if not impossible in economic and practical terms, to print a single unit of something. This is why Print on Demand developed only after digital printing was invented.]
'Print on Demand is also a trademark of Cygnus Business Media and a business model. This is why POD is often associated with self-publishing and vanity presses.
Many traditional small presses have replaced their traditional printing equipment with POD equipment or contract their printing out to POD service providers, and many university presses and other academic publishers use POD services to maintain a large backlist. Even midsized presses may use POD in special circumstances, such as reprinting older titles that had been out of print or doing test marketing.