Covering Materials:

Leather: Leather was the primary covering material for books until the third decade of the last century. It is only later that the commercial publishers began to use cloth as a covering material. Goatskin, sheepskin and calfskin have also been used in the past. Calfskin was popular in the sixteenth century and sheepskin in the seventeenth and eighteenth century. Morocco was widely used in the eighteenth and the nineteenth century and is still in use today. 

Because of its pliability, strength and permanence leather is considered to be an ideal covering material for forwarding, finishing, tooling and lettering purposes.

Kinds of leather: The principal leathers used in fine bindings are:

Morocco: Levant morocco or real morocco is made from goat skin. Its characteristic features are its long fibre and prominent grains on the surface. This material should only be used for very valuable books which require a handsome and dignified binding. It is very durable and satisfactory provided is of good quality. There are varieties of morocco like Persian, Niger and Levant Morocco, of which Levant Morocco is the best.

Roan: This is a kind of inferior skin with a different grain and surface from Persian morocco and is a cheap leather often used for certain classes of books like, less popular works of travel, science, theology, fiction, etc. This is now largely superseded by cloth binding.

Pigskin: It is the strongest leather of all, and also the most durable for much used heavy books. All reference works as such as dictionaries, atlases, directories and other volumes which are constantly used are to be bound in this because it is hardwiring and also attractive in appearance. It is most useful for binding large volumes like newspapers. The main defects are its thickness and inflexibility.

Sheep skin: Sheep skin is a good quality leather and is attractive, brown in colour, very soft and durable. Proper tanning is essential to retain its original quality. It is used for rebinding and covering old books. 

Calf leather:  Though nondurable, calf leather is smooth, delicate and beautiful. Since strength or durability is more important than appearance in book binding it is considered quite inadequate for binding purposes. 

Imitation leather:  Increasing cost and unavailability  of real leather and also the available technology has given way to imitation leather and leather cloth. These are cheaper stronger than real ones and as such have substituted for leather. It is available in a variety of qualities, shades and colours.  It is available in a variety of qualities, shades and colours. It is stain resistant, has good finish and has grained surface but is sticky. 

Cloth: It is claimed that good leather and good binder's cloth have little difference in durability and cost. Good quality binder's  cloth is  amazingly  durable and makes excellent covers for all types of library materials: The technology now available has made these cloth water proof and oil resistant, with several varieties in graininess and colour combinations.