Many books were not available to the public because of government censorship. Governments have sometimes banned or restricted access to certain books for various reasons, including political, religious, or moral concerns. The goal behind such actions is often to control the spread of ideas or information that might be seen as threatening to the status quo or national security.

For example:

During times of political oppression, governments might censor books that criticize the regime or promote dissent.

Religious authorities might restrict access to books that contradict religious doctrines or beliefs.

In some cases, books with content deemed immoral or inappropriate for certain age groups may also be censored.

Censorship of books has been a historical issue in many countries, and it continues to be a topic of debate in terms of freedom of expression versus national or cultural interests.