Books with blank pages used for assembling and presenting a collection, or any unpublished sets of pages that are bound or loose-leaf and have other materials affixed to them or writing or other images made on them. The volume may have been constructed with blank pages that were intended to have materials affixed, or it may have been assembled after having had materials affixed to separate pages.

Source: AAT

http://vocab.getty.edu/page/aat/300026690