The craft of bookbinding began simply, with the use of boards to protect parchment manuscripts. By the 2nd century, sheets of parchment were being folded and sewn together. During the Middle Ages, the practice of making fine bindings for these sewn volumes rose to great heights; books were rare and precious articles, and many were treated with exquisite gilded and jeweled bindings. What is the uncommon practice of binding books in human skin, a technique dating back to the 17th century, called? Discuss