LONDON — Even though "Mein Kampf" is banned in Germany, Adolf Hitler's book is still one of the most sought-after titles for German readers over the Internet.

The popularity of "Mein Kampf" among German customers is second only to Elizabeth George's detective novel "In Pursuit of the Proper Sinner," according to a report by Internet bookseller Amazon.com at last month's Frankfurt Book Fair.

Amazon's competitor, barnesandnoble.com, in which the German publishing giant Bertelsmann has a 40 percent stake, said its sales put the book in fourth place. Bertelsmann has asked barnesandnoble.com to cease delivering the book to customers in Germany.

While it is not illegal for Germans to own copies of "Mein Kampf," written by Hitler in 1924, its sale in Germany is banned under a law that prohibits the dissemination of Nazi propaganda.

Annotated copies are available for academic purposes, but it is difficult for ordinary Germans to obtain a copy.

The question posed by the high sales figures on Amazon is whether the demand over the Internet is from neo-Nazis or from other readers with curiosity in the subject.

German politicians are worried, and the Bavarian Justice Ministry has announced that it will take legal steps to halt the sale of Hitler's works by U.S.-based Internet companies.

"It's disgusting," said German Justice Minister Herta Bauebler-Gmelin. "We don't want that stuff, and those companies are breaking German law."

In fact, however, there is little that the Justice Ministry can do about online bookstores outside the country. They must rely on the good will of the stores to police themselves — unless, as in the case of American Gary Lauck, they cross the border.

In 1995, Lauck, who had been spreading Nazi propaganda on the Internet, was arrested in Denmark and extradited to Germany, where he was tried in Hamburg and sentenced to four years in jail.

Lauck was recently arrested in Nebraska for illegally trying to obtain a gun permit.

Meanwhile, online companies are defending themselves on the grounds that they are upholding freedom of speech. "The decision as to what one chooses to read should be left to the individual. We are not censors," said an Amazon.com spokesperson.

Among commentators in Germany, the debate has assumed a different dimension: Is the ban doing more harm than good?

Writing in the liberal Berlin daily Der Tagespiegel, Hans Monath declared that the book's "myth-like status will not be dispelled by banning it and making it taboo, but by letting it be freely available, accompanied by explanatory notes."

The German authorities are apparently unconvinced, and seem determined to maintain the ban, at least until the copyright expires in 2015.

In the meantime, anyone who wants to publish "Mein Kampf" or quote extended passages from it must seek permission from the Bavarian Finance Ministry. Most requests are rejected, according to ministry spokesman Bernd Schreiber.

The sole exception is for requests that come via Israel. One unintended consequence of this exception is that Palestinian booksellers in the West Bank town of Ramallah report that "Mein Kampf" is rated sixth on their bestseller lists.

The book is freely available in Britain and the United States because the publishing house that was originally responsible for "Mein Kampf" sold them the license in the 1930s, but this still raises awkward questions about what to do about the profits.

British publisher Hutchinson, which sells 3,000 copies a year, disdains what it describes as "dirty money." It tried to hand over its profits from sales of "Mein Kampf" to Bavarian authorities, who declined the offer. So, too, did various Jewish charities and the Red Cross.

Eventually, a British charity was persuaded to accept the money, but only on the condition that it be allowed to remain anonymous.