A reprint is publishing a book again after it has already been published. This can happen for several reasons, including to make the book available to readers again, to fix mistakes made in the original printing, or to include new information that has become available.
Reprints can be produced by the same publisher who created the initial version of the book or by a different publisher altogether. Occasionally, when a book goes out of print, and another publisher buys the right to reprint it, this new publisher buys those reprint rights from whoever holds the copyright to the book. In these cases, if the original publisher wants to keep selling copies of a book once it has gone out of print, they have to allow someone else to publish a reprint edition instead of just doing it themselves.
In the realm of publishing, reprints come in two forms: trade and mass-market. A trade reprint involves producing more book copies in the same style as its initial incarnation. However, if a new printing appears in a smaller and cheaper format, it’s classified as a mass-market reprint.
Although the original publisher frequently executes reprints, other publishing houses can also undertake them; such instances are known as licensed reprints.
Far from being an incidental sideshow within the book-publishing ecosystem, reprint represents an integral aspect: this is how works get published again after their initial release — thereby enabling fresh cohorts of readers to discover (or rediscover) them. Moreover, it’s not uncommon for people who enjoyed something when they were younger to want to own a copy that’ll evoke memories via rereading, and if said work happens to be part of a series, then keeping early installments ‘in print’ via reprinting makes later ones easier to sell.