Many authoritarian regimes censor books for political reasons.
But Iran goes so far in also tampering with books for self-claimed religious reasons that the Islamic republic's censors form a league of their own.
The latest example came this week, when censors refused a publishing house permission to reprint an edition of one of the country's best-known classical epic poems.
The Ministry of Culture and Islamic Guidance decided that some parts of the epic poem "Khosrow and Shirin" by Nezami Ganjavi needed reworking, despite the fact that the book-length masterpiece has been a classic of Iranian literature for 831 years.
The news not only astounded the publishing house, which had expected routine approval when it sought to publish its eighth edition of the book, it also shocked Iran's intellectual class, despite decades of inurement to the censors' heavy hand.
Iranian poet Simin Behbahani
"This poem existed for nine centuries and...Iranians were Muslims during those nine centuries," says Iran's best-known contemporary female poet, Simin Behbahani. "No one [during that time] had any objections to [the] 'Khosrow and Shirin' poem and didn't think of censoring parts of the poem.... Nothing would be left [of the poem] by now, if they had. Those who talk about censoring the poem should be ashamed."
The Ministry of Culture and Islamic Guidance has given no official explanation for its decision to belatedly censor the epic. But one objection reportedly concerns the poem's reference to the heroine Shirin embracing a male body.
A Million Forms Of Indecency
That the body is that of her murdered husband and the embrace is a key to understanding her suicide at the end of their tragic love story seems not to have mattered one bit to the censors.
If the embrace is indeed the reason for the censorship, it would be in line with decades of similar objections by Iran's censors to anything they construe as indecent. According to their guidelines, indecency can come in a million unexpected forms.
Faraj Sarkouhi, who edited the Iranian cultural weekly "Adineh" before he was imprisoned for "propaganda" in the 1990s and fled to Germany following his release, says that Iran's censors are obsessed with the idea that romance can be a corruptive force in society. They make Iran a hell for literature, without regard to whether it is contemporary or classical.
"It is very harmful for literature, because in stories you write about the life of the people; and in the life of the people there is love, there is sleeping together, kissing, drinking, good things and bad things, because the human being has very different aspects," Sarkouhi says.
"In a story you have to portray all of these different aspects. But they don't want some parts of life to be mentioned in literature and in this way they really kill our contemporary writing and they also censor some parts of our classical literature."
At times, the censors' zeal reaches levels of absurdity that stretch the imagination. Authors' works -- including translated versions of world literature -- are regularly modified to make them conform to the censors' own standards.
Sarkouhi notes that the dialogue in a recent Iranian version of one of the novels of German-Swiss author Hermann Hesse was altered so that a reference to wine instead became a reference to coffee.
The censors did not care that the change left a character saying incomprehensibly that the high alcohol content in the coffee he had just consumed had given him a headache.
Similarly, if a man and a woman who are not married are in love, the censors feel no compunctions about adding a paragraph to marry them and legalize their situation.
For The Good Of Society
To defy the censors and still describe the reality of their characters' lives accurately, some contemporary authors turn to coded language.
Thus, a phrase such as "they kissed and that night slept together for the first time" becomes "they looked at each other and then told one another it's better to have some more time." The phrase "have some more time" has become a synonym in Iran for going to bed.
But classical authors, long dead, are unable to play such games and, in most readers' minds, should be untouchable anyway.
If the author is someone like Nezami Gangeva, whose "Khosrow and Shirin" and another epic poem, "Layla and Majnoun," are pillars of both Persian and world literature, the public's feeling of indignation is still stronger.
Equally galling for many Iranians is the censors' claim they are doing it all for the good of society.
Poet Behbahani, who is 84 and a cultural pillar in her own right, says she finds it incomprehensible that officials are concerned with the morality of a woman embracing a dead body when people who protested against Iran's last presidential election were widely reported to have been raped in detention.
"In this country, they take a young, poor boy to prison and rape him there," Behbahani says. "We have heard about it many times and I hope it is a lie. Is it possible that those able to rape such an innocent and fragile creature can also think one would derive pleasure from embracing a dead body?"
Nonetheless, if outrage is high over the censors' latest crackdown, there is little ordinary Iranians can do but hope the refusal to publish "Khosrow and Shirin" will change in the future.
Sarkouhi notes that the intensity of the censorship has ebbed and flowed over the decades since the 1979 Islamic Revolution.
All Books Are Vulnerable, Even The Most Venerable
He says it was even heavier during the last decade, when the Ministry of Culture and Islamic Guidance regularly banned the republication of up to 70 percent of previously published books. Today, he estimates, the number of license refusals for republication has eased to about 50 percent.
Exiled Iranian editor Faraj Sarkouhi
The ultimate responsibility for writing the censors' guidelines lies with one of Iran's many powerful committees that date back to the Islamic Revolution.
Half the members of the Council for Cultural Revolution are appointed by Iran's clerical leadership and the other half are named by the parliament. It's the same body that closed Iran's universities for five years after the revolution in order to Islamicize them.
Meanwhile, while the council prepares the guidelines that the Ministry of Culture and Islamic Guidance follows, there are additional forces that regularly take authority into their own hands to bedevil publishers' efforts to get official permission to print books.
Those other forces include clerics, Friday Prayer leaders, the Islamic Revolutionary Guards Corps, the Basij militia, and the Information Ministry, just to mention a few.
"Books are a very sensitive problem in Iran," Sarkouhi observes. As this week's events illustrate again, that means not just some books but all books -- no matter how venerable they may be.
Radio Farda correspondent Elahe Ravanshad contributed to this report