Note the Sewing pattern when Deconstructing a Book
When you are deconstructing a book and you know you are going to re-sew it in the traditional manner with needle and thread. Make notes on a piece of paper that will help you remember what you discover while you are taking it apart. That way it will be easier to re-sew it according to the way it was done originally. This is typically only needed for more rare books and only if the client is willing to foot the extra expense. Other sewing options include Kerf sewing which destroys some of the inner margin, or there is a sort of tacking together sewing that is possible where you line the spine and then sew through it only for the loose signatures.