In December 2019 English Wikipedia suppressed the rendering capability of Template:Wikipedia books (related =Template:Book bar & Template:Books-inline) and removed the Book Creator from the sidebar after a community discussion about effectiveness.
As the Book Creator no longer generates copies of Wikipedia books, its primary working feature directs users to order printed Wikipedia books from PediaPress, a third-party company which has a longstanding agreement with the WMF. Editors in discussion valued the user experience of Wikipedia readers over the business prospects of PediaPress and felt that the template and sidebar link were no longer justifiable.
The namespace and its transclusions were retained in the hope that the WMF would come up with a solution. As a result of then-anticipated future solutions, template transclusions were not removed from articles. See Suppress rendering of Template:Wikipedia books for more information.