What is print-on-demand (POD) publishing?

Print on Demand publishing, or POD, is a method of book printing using digital technology that makes it easy and cost-effective to produce books as they are ordered, either one at a time or in larger numbers. Instead of a more traditional mode of printing, which only prints a large number at one time, POD is an "as needed" printing model so there are no wasted books, no need to store them and no wasted costs. This also means that the book can be available for an extended period of time, instead of the book being "out of print" after one print run.