Imagine you are on a plane Europe. You notice that the passenger next to you is read ing a book in a foreign lan guage, and the author’s name catches your eye: Adolf Hitler. The book is “Mein Kampf.” Do you assume he is (a) an academic; (b) a Nazi; (c) an Islamist? Leave aside (c) for the moment, and consider (a) and (b). There is no German edition of “Mein Kampf” in print because ever since 1945 the Bavarian state government, which inherited the copyright from Hitler’s publisher, has refused to allow the book to be republished. Some countries also try to control the trade in second-hand copies, millions of which were printed during the Third Reich. Not only in Germany but also in Israel, Switzerland, and Norway it is illegal to buy “Mein Kampf.” In Austria ownership is an offense, while in the Netherlands it is the vendor who is penalized. Now a leading German academic historian has stirred up controversy by calling for Germany’s de facto ban to be lifted before the copyright expires in 2015. Professor Horst Möller, director of the Munich Institute for Contemporary History, argues that censorship merely adds to the book’s notoriety: “As long as ‘Mein Kampf’ is not available in a carefully annotated edition, there will be no end to the often simple-minded speculation about what is actually in the book,” Mr. Möller said last week. “An academic edition could break the peculiar myth which surrounds ‘Mein Kampf.'” To any liberal, this sounds reasonable enough. In the London Times, the columnist and author, Ben Macintyre, applauded Mr. Möller’s proposal: “‘Mein Kampf’ is a historical relic that has retained its power to horrify,” he wrote “It should be preserved and exhibited in the same way as Auschwitz, the killing fields of Cambodia and Holocaust museums everywhere.” Recalling with pride that the Times had serialized extracts from “Mein Kampf” in 1933, Mr. Macintyre declared that the paper had been right to do so: “Even so, the Editor of the day George [sic] Dawson was plainly holding his nose as he placed ‘Mein Kampf’ in the public domain.”

Let me declare an interest. Mr. Macintyre’s father, the historian Angus Macintyre, taught me at Magdalen College, Oxford, 30 years ago. Angus would have been amused that nobody at the Times thought to correct the reference to Geoffrey Dawson, one of the most celebrated of its past editors, but evidently now forgotten there. Ben Macintyre is a friend of mine. But his assumption that “Mein Kampf” is a “historical relic” and his recommendation that “everyone should read it” are not only wrong, but also dangerous.

He acknowledges the likely objections of Holocaust survivors, but only to dismiss them: “Whatever sympathy one may feel for those who suffered, no book should be banned, however pernicious.” It is not a matter of sympathy for Hitler’s victims — it is a matter of lending respectability to contemporary anti-Semitism, which is undergoing an alarming revival in Europe and beyond. It isn’t only the stupid and the ignorant who were influenced by “Mein Kampf,” intellectuals read it too. They didn’t take Hitler seriously, with disastrous consequences. Later in the 1930s, it was the same editor, Geoffrey Dawson, who turned the Times into the leading mouthpiece of appeasement. People sometimes say: “If only British leaders had read ‘Mein Kampf’ — they would have known what to expect from Hitler.” Well, many of them did read it — and they didn’t know what to expect.

I do not necessarily object to Mr. Möller’s idea of a scholarly, annotated German edition of “Mein Kampf.” After 2015 the book will be in the public domain anyway, so it would be best if it came with as many health warnings as possible. But such academic editions are prohibitively expensive. Mr. Macintyre’s contention that “Mein Kampf” should be “cheap” so that “everyone” could read it strikes me as culpably naïve. Historians do not need cheap editions; propagandists do.

President Ahmadinejad’s threat of a second, nuclear Holocaust and the reaction — or lack of it — in Europe should be enough to tell us that anti-Semitism is still dangerous. That brings us back to our passenger reading “Mein Kampf.” He is most likely to be neither (a) an academic nor (b) a Nazi, but (c) an Islamist. And the foreign language is most likely to be not German, but Arabic.

Nazi literature does not just circulate in the hermetic, deranged mental universe of Islamism — it is ubiquitous. That is partly because the movement has been influenced by Nazi ideas from its inception, but also because it has a similar demonology to Hitler’s: purging of the West in general and Jews in particular.

When the journalist Richard Littlejohn was making a TV documentary on anti-Semitism in Britain, he was shocked to discover how easy it was to buy a copy of “Mein Kampf” in ordinary Muslim-owned stores. He found one on sale a few yards away from the house near Oxford Street where the Blair family will move when they vacate Chequers, the official prime ministerial country residence.

German denazification took a long time — and it included eradicating the influence of “Mein Kampf.” What an irony if the same book were to become the vehicle for the renazification of Europe — only this time not under the swastika, but the crescent.