If pages are loose in the front and/or back of your book, they need to be stitched onto the rest of the text block. I use a needle instead of a drill bit, and drill a series of tiny holes through the top sheets diagonally into the spine about 1/4 inch down. Then I attach new endpapers to the text block, and add new super. Only then can the strong text block be glued into the leather cover.
If pages are loose in the middle of the book, if the book is thicker than 1 inch, it needs to be oversewn. If it is less than 1 inch thick, it can be side stitched by hand.
