The 10 most unexpected things books are made of

Human skin: In the past, some books were bound in human skin, which is known as anthropodermic biblioprinting. Although this practice is now considered unethical, some 16th-19th century books bound in human skin are still in circulation.

Metal: Metal books are made by etching text into thin sheets of metal, usually copper or brass. Such books were popular in the early 20th century for advertising purposes, but can still be found today as decorative objects.

Ice: In 2005, an artist created a project called "The Ice Book" by making a book out of frozen water. The pages were made of ice and illuminated from the inside with LED lights.

Chocolate: Chocolate books are a popular gift and are made by cutting text and images into blocks of chocolate. The pages are then stapled together to make a book that can be eaten.

Glass: Glass books are made by etching text onto glass plates. Such books are often used for decorative purposes and can be backlit to create a unique display.

Stone: Stone books have been found in various cultures throughout history. These books were usually made by carving text and images into stone tablets or slabs.

Wood: Wooden books were popular in the Middle Ages and were often used for religious texts. Pages were made of thin slats of wood that were covered with parchment or vellum.

Bamboo: Bamboo books were popular in China during the Tang Dynasty. Pages were made of thin strips of bamboo, which were held together by silk or leather.

Papyrus: Papyrus was used in ancient Egypt to make books. Pages were made from the core of the papyrus plant, which was flattened and woven to create a sturdy surface for writing.

Recycled materials: Today, many books are made from recycled materials such as paper, cardboard, and cloth. Such books are often created by independent publishers and are a way of reducing waste and promoting sustainable development.