Prefaces are divided into author's prefaces, non-author's prefaces and translator's prefaces, and different subjects write different prefaces. Among them, the author's preface is the preface written by the author himself, which is generally used to explain the idea, significance, main content, key points and characteristics, readers, related writing process and situation, arrangement and style, scope of application, readers' reading suggestions, explanations on the revision of reprints, introductions of people who assisted in writing and their thanks.

The non-author preface is the preface written by the author inviting famous experts or institutions to write this book. The content is generally to recommend works, evaluate works realistically, and introduce the author or people and things involved in the book.

The preface of a translator usually focuses on the translation intention, and some also include some transactional explanations in the translation process. Generally, the title is "translator's preface", and the simpler content can also be titled "translator's preface" or "translator's words", which usually comes before the catalogue.

Preface is also called preface, abbreviated as preface. An article written before the text of a work. Generally, the author explains the process of writing a book, or others introduce and comment on the content of the book. Preface can be roughly divided into self-sequence and substitution. Among them, the writer should generally explain its content, writing reasons, process, characteristics and related things that happened in the writing process. When writing a preface, it is generally to introduce and comment on the main contents and characteristics of the book.