"Backlist" refers to a collection of books that were published in the past and are still available for purchase, even though they may no longer be brand-new releases. Full definition
Be aware that some publications will not publish book reviews of backlist titles in their magazines and on their websites. (aer.io)
As digital publishing began to enable the reissue of backlisted titles as ebooks, «agents needed to get those ebooks out into the world. (publishingperspectives.com)
Especially for backlist books that were sold to traditional publishers and changed significantly, would any authors be willing to «release» (epub or print) both the «original motion picture» (traditional published text) and the «director's cut» (a different version a bit longer that the author liked better)? (madgeniusclub.com)