Iran's ministry of culture and Islamic guidance vets all books before publication. Three censors read each book to make sure it conforms to Islamic values. Censorship might apply to only a word, a sentence, a paragraph or sometimes a text as long as a dozen pages and the result would be given to the publisher after a long procedure that might last a year or two. Censors, who sometime use computer software to look up "unIslamic words", go as far as advising writers to substitute certain words with other "appropriate" phrases, should they wish their book to be approved. Publishing houses will be given negative points if they persist in sending too many books to the ministry which they deem to be unsuitable, encouraging self-censorship.

Speaking to the Guardian, Mehdi Navid, who has translated Richard Brautigan's In Watermelon Sugar into Persian, called some changes ridiculous. When publishing a book by Charles Darwin on evolution, he said, the ministry asked the publisher to add an introduction to the book explaining that Darwin's views were unIslamic and untrue and the book was to be published to expose the wrongdoings and the decadence of the west.