Hide glue is a traditional adhesive made from animal collagen, typically derived from the skins and bones of animals. It is commonly used in woodworking, especially in the construction of fine furniture and musical instruments, due to its strong bond and ability to be easily reversed with heat and moisture. This glue comes in granule or liquid form and is often applied warm. Once it cools, it forms a strong bond that can be sanded and finished like wood. Hide glue is favored by many craftsmen for its historical significance and the unique properties it offers compared to modern synthetic adhesives.