The back of a hardcover book is different from a paperback book. The back of a paperback book is generally flush, while hardcover books can be divided into hard back, cavity back, and soft back, but each of these three binding methods has its own advantages and disadvantages.

1、硬背装成书挺括、坚固，可放置书架上长期收藏，但翻阅时不易完全摊平；

1. The hard back is sturdy and sturdy, and can be stored on a bookshelf for long-term storage, but it is not easy to fully flatten when flipping through;

2、腔背装摊得平，成书外观比较平整、美观，但长期置放在书架上似有软塌之感；

2. The cavity back decoration is laid flat, and the finished book has a relatively flat and beautiful appearance, but it seems to have a soft and collapsed feeling when placed on the bookshelf for a long time;

3、柔背装既能摊平，也比较坚固，只是外观上较以上两种柔弱些。

3. The soft back outfit can be flattened and relatively sturdy, but its appearance is slightly weaker than the above two.

不过，我国的精装书多采用腔背装。 精装书印刷的装订工艺主要有制书心、制书壳和上书壳3个过程。书壳按面料分又分为：整面书壳和接面书壳两种。

However, most hardcover books in our country use cavity back binding. The binding process of hardcover book printing mainly includes three processes: making the book core, making the book case, and loading the book case. Book cases can be divided into two types according to the fabric: full face book cases and joint face book cases.

整面书壳：是由一张完整的封面材料制成，即书脊和封面封底采用整片的同一种材料制成。

Full face book case: It is made of a complete cover material, that is, the spine and back cover are made of the same material as the entire sheet.

接面书壳：封面材料不是一整块，通常是封面和封底用一种材料，书腰用一种材料并接而成。即书脊和封面用不同材料制成，通常以织物作书脊，以纸张裱糊在硬纸版上作封面，这种形式一般多为圆脊不带护封。在精装书封壳制作中，除塑料压制的活套书封以外，常见精装书封壳是由硬质纸板、软质封面、中径纸等经加工所组成的。

Joint Book Case: The cover material is not a whole piece, usually the cover and back cover are made of the same material, and the book waist is made of the same material. The spine and cover of a book are made of different materials, usually using fabric as the spine and paper mounted on a hard paper plate as the cover. This form is usually a round spine without a protective cover. In the production of hardcover book covers, except for plastic pressed looper book covers, common hardcover book covers are composed of hard cardboard, soft covers, medium diameter paper, and other processed materials.

表面层的封面材料通常用各种软质材料，如织品、皮革，各种涂布料中的漆涂布、漆涂纸、PVC涂布纸、覆膜纸、特种纸等制成。制作时，可以整幅面糊制成书封壳,可用两种材料拼幅联接制成书封壳。

The cover material of the surface layer is usually made of various soft materials, such as fabrics, leather, and various coating materials such as lacquer coating, lacquer coating paper, PVC coating paper, laminating paper, special paper, etc. When making, the entire dough can be used to make a book cover, and two materials can be pieced together to make a book cover.