The books are sewn together, one set of pages at a time. In class we used a special book binding needle (which is very thick and long) and a waxed linen thread. The sewing stitch we used is known as ‘kettle’ stitch, although there are lots and lots of different stitches and techniques used for sewing together pages in book binding.
Each hard backed book has 2 cover papers, one for the front and one for the back, which attaches to the front page of the book pages, and the hard back cover.
Cover pages are often made with special papers and traditionally may be marbled. They are cut to be exactly the same size as your booklet pages.
You attach your cover paper to the front and back of your booklet bundle, using specialist book binding glue. There are a whole world of specialist glues used in book binding, but the one we used in class was a wheat starch paste.
Just run a thin swipe of glue down the spine edge front and back and stick your cover page to the thin glue line.