Also called edition binding, this method results in what is commonly called a hardcover book. It is the most expensive option yet also the most durable. Stacked signatures are gathered and sewn together for strength. This book block is trimmed on three sides and then glued into a spine, front cover, and back cover (a single unit) made of binders board covered with paper or cloth. The first and last sheets (end-sheets) are then pasted to the board. To reduce the cost of this binding method, you can set perfect-bound book blocks into cases rather than first sewing the signatures together and then gluing them into the covers.