The paperback is a particular binding style aimed to produce books at competitive costs.
The cover is made of coated board or similar material and glued to the spine.

Hardback

Casing: mostly used for editorial binding, it ensures higher solidity compared to paperback. The cover is made of paper (rather than canvas, leather or other material) glued to thick board; it can be bound separately from the book.
Hard-bounding: it is hand made and very resistant, particularly suitable for art books. The cover is made of board, same as for the casing but the covering materials are more valuable; it is bound on

This particular type of binding consists of a metallic or plastic spiral, produced in many different colours and finishing, and can be used for many products having different specs. Its unique flexibility makes it suitable for notebooks, road maps and traditional desk or wall calendars.