ISTANBUL — I recently spent a few days in Malaysia, where I was promoting the publication of the Malay edition of my book, “Islam Without Extremes: A Muslim Case for Liberty.” The publisher, a progressive Muslim organization called the Islamic Renaissance Front, had set up several talks for me in Kuala Lumpur. As any author would be, I was happy to learn that the team was enthusiastic about my book and had been getting good feedback from audiences and readers. But I was troubled by something else that I suspect many Muslim authors have experienced: My publisher was worried about censorship.

The risk, I was told, was that the Department of Islamic Development, a government body that “was formed to protect the purity of faith,” could ban the book if it was viewed as violating traditional Islamic doctrine.

So far, the Malaysian government has not banned my book. But if it did I wouldn’t be surprised. The department has already outlawed more than a thousand books translated into Malay. Charles Darwin’s “On the Origin of Species” was banned because, according to the home minister, it “goes against Islamic teachings,” and even “endangers public harmony” — whatever that means. “Islam: A Short History,” a fairly sympathetic study by the best-selling author Karen Armstrong, was similarly banned for being “incompatible with peace and social harmony.”

Malaysia isn’t an anomaly in the Muslim world. In the more extreme case of Saudi Arabia, the Ministry of Information can censor any publication it wants, and the religious police can confiscate books if they detect what they perceive as a hint of blasphemy. Even the Bible, the world’s best seller, is banned in Saudi Arabia — no matter that the Quran praises it. In Egypt, under the iron fist of President Abdelfattah al-Sisi, a range of literary works can be outlawed. Last month, a novelist was sentenced to two years in prison for “violating public modesty.”