The average book is a5, and the book-sized paper is A5. Generally speaking, our books are relatively smaller than a4. And our "A" refers to the paper of a book. Generally speaking, the smaller the number, the bigger the paper. The paper of A 3 will be bigger than that of A 4, so it is smaller than that of A 4.

Characteristics of books

Books are obviously independent of each other: each book usually has its own unique title, clear and focused theme, independent and complete content. The content structure of books is systematic: books generally introduce related contents systematically and orderly according to certain themes, viewpoints and certain structural systems. The view of book content is relatively stable: the content of books generally does not emphasize news and timeliness like newspapers and magazines.

Books often focus on introducing mature, reliable and relatively stable ideas in a certain period. The style of book content is consistent: the content of a magazine often coexists with multiple styles, but the content of a book usually adopts the same style. Sci-tech books generally have strict and unified requirements in style format, terminology, chart form, measurement unit, digital use and so on. The length of the book is flexible. Different from periodicals, the length of books can be flexibly mastered according to needs.