Felipe Fernández-Armesto

I am not yet up there with Salman Rushdie or Tintin. Disappointingly, from my publishers' point of view, no one has yet pronounced a death sentence against me. Regrettably, the Commission for Racial Equality has not boosted my sales by wanting to ban my work from public libraries. But I have just achieved the noblest accolade available to a writer: I have become a victim of censorship.

Various books of mine have appeared in Chinese translation without mishap. But now work on a Chinese edition of my history of ideas, Ideas that Changed the World , which appeared in English in 2003, has had to be suspended because I will not agree to excisions demanded on political grounds. The book is radical in one sense: like most of my books, it takes an experimental approach. I treat ideas as purely mental facts, start with presumptions about hominid thinking, postpone mention of Ancient Greece until the reader is a third of the way through the book, and cover the subject by taking one idea after another and dealing with each discretely. None of this - which I intended to provoke readers' outrage - offends the censors. Their objections, however, are supremely interesting: they reveal truths about China that I had previously overlooked.

The objectionable content falls into four categories. First, pejorative references to Mao are intolerable. I am not allowed to extol Mao's "dogged perseverance (which he later misrepresented as genius)" nor say that under his rule "official crime rates were low, but people were brutalised more by habitual punishment than occasional crime". It is inadmissible to quote Stalin's famous judgement that Mao "doesn't understand Marxist truths - or maybe he doesn't want to understand them". Naively, I was surprised by the censors' attitude, since the present Chinese regime has effectively disavowed Mao's economic legacy without reservation. Still, safely buried, he must be praised.

Secondly, generalisations that might imply adverse criticism of China are anathema. It may seem fairly anodyne for me to point out that "Hegel argued that the state's will always took precedence over its citizens", but the sentence captions a picture of the 1989 democracy demo in Tiananmen Square.

Thirdly, Chinese officialdom will not allow the US to appear in a good light. To say that the US example has helped spread freedom and democracy, or even to quote inspiring rhetoric from the Declaration of Independence, is out of the question. If I complied with the censors' demands, the effect would warp coverage of America: my animadversions on the trashiness of the American dream and the folly and foulness of current US foreign policy would remain intact.

The reasons for Chinese self-distancing from the US become clear when one looks at the final category of exclusions from my book. They are all references to Islam - especially any that might clash with the self-image of the Iranian regime. I may not raise a question about the sources of Muhammad's inspiration or point out his indebtedness to Jewish traditions. I am not allowed to allege that Ayatollah Khomeini had "an almost insane conviction of self-righteousness" or even that he hated most forms of modernisation - a point about him he would surely have been happy to endorse.

There are some strange anomalies. The strangest objection is to this pair of sentences: "Christianity - unlike Islam and, so far, Buddhism - has effected 'spiritual conquests' in every type of cultural environment. The comparison raises the presumption that the more culturally adaptable a religion is, the further it spreads." I guess that the censors must think this is a comparison of value between Christianity and Islam - which of course it is not.

In some ways, Chinese censorship would grant me surprising licence - for instance, to denounce anti-Semitism, question capitalism, challenge fundamentalisms of all kinds, and insist that "Sharia needs adaptation to an increasingly inter-connected world in which common assumptions about human rights owe more to Christian and humanist influence than to Islam". I am sure, moreover, that I have included opinions equally offensive to excessive sensibilities of all kinds in previous books, which have appeared in Chinese translation without cavil.

So, on the face of it, it looks as if Chinese censorship is getting stricter. From their objections to my work, you can see the trajectory of current Chinese policy: entente with Iran. It would make a formidable and frightening alliance. There is a lesson here for intelligence-gatherers: look at what the Chinese are censoring today in order to predict what they will do tomorrow. Meanwhile, I feel flattered. I must forgo a thousand million potential sales; but a censor, at least, has read my book attentively.

Felipe Fernández-Armesto is Prince of Asturias professor of history at Tufts University in the US.