1. Illegal, infringing and pirated books: These books may violate copyright laws and be copied, disseminated or sold without authorization.

2. All kinds of books that violate the regulations on publishing management: These books may violate the relevant regulations of the state on publishing management and be published without approval or in violation of the examination and approval regulations.

3. Overseas books imported through informal channels: These books may enter China through illegal or unauthorized channels without relevant approval procedures.

4. Pornographic, horrible, cruel, violent and bloody books: These books may contain obscene, disgusting or excessively violent contents and are not suitable for public libraries to collect and borrow.

5. Books that spread feudal superstitions and promote narrow nationalism and racism: These books may promote unhealthy values, incite hatred and discrimination, and do not conform to the principles of equality, openness and tolerance generally advocated by libraries.

6. Books that do not conform to the socialist core values: These books may contain contents or opinions that are contrary to the socialist core values and do not conform to the purpose and policies of the library.

7. Books with low style, poor originality and patchwork: These books may be of low quality and lack uniqueness and originality in content, which does not meet the library's requirements for book quality.

8. Books with a long history and outdated content that have no use value: These books may lose their use and reference value because of outdated content.

9. Books with poor printing, binding and editing quality, too many mistakes and omissions, too small font and too high price: These books may be of poor quality, including problems in printing, binding and editing, which do not meet the library's requirements for book quality.