The first books were made about 4,000 years ago by the Egyptians who took flattened layers of papyrus stalks to make sheets. The ‘books’ they made were sets of rolled papyrus sheets – quite distinct from a book of today. In the middle of the fifth century, parchment (sheep skin) replaced papyrus. Parchment sheets were set on top of one another and bound down one side with leather thongs. But it was in the Middle Ages that books as we understand them now evolved. Vellum (calf skin) was made into sheets, and each bit was folded down the centre. Four vellum sheets made eight leaves and was considered a section. Unlike parchment, vellum was thick enough to be written on both sides. Finished sections were sewn together down the back fold (the backbone) and covered with wooden planks front and rear. The boards and back were subsequently covered with leather; the result was a book much like that of today.