Two pieces are measured and cut out of an Archivart board -- the first is cut to the width of the book so that it folds over  on each edge (3 times the width + the thickness twice). The same is done with the second board, using the height of the book. 

These two pieces are then "crimped" on a machine (folds put in) at the places where they need to fold to make an enclosure.

The second piece is then measured and crimped, following the same process.

Once the two pieces are crimped, they are are then checked to make sure the book fits properly.

The two pieces are then glued together with PVA where they come together in the middle when laid in the form of a cross. After drying, eight holes are are put in with a chisel, and the box is threaded with linen tape so that it can be tied closed.