primary stitching without a cover

The textblock only is stitched, without any cover. It is possible to find separate endleaves at the left and right of a stitched bookblock, though this is relatively unusual. More typical are wrapper-type endleaves which, if there is no additional cover present, do in effect become a cover, in that there is no logical mechanical distinction between a wrapper-type endleaf of plain paper and a sheet of decorated paper .