Osama Bin Laden has seemingly propelled a book by an obscure historian into the US bestseller list, by endorsing it in an audio message aired on Thursday.
Bin Laden apparently said Rogue State was "useful" to read
Rogue State: A Guide to the World's Only Superpower had reached number 21 on the Amazon list by Sunday, leaping from below the 200,000 mark.
Author William Blum, 72, said he had no regrets about the endorsement.
The 320-page book is highly critical of US foreign policy, and says the US war on terror is doomed to failure.
The message, thought to be from Bin Laden, contained threats of new attacks on the US, but also a call for a long-term truce.
But he also told Americans: "If Bush carries on with his lies and oppression it would be useful for you to read the book The Rogue State.'"
Bin Laden quoted a line from the book that the writer, if he became president, would end US interference in the nations of the world.
Mr Blum, speaking from his Washington apartment, said he was "surprised and even shocked and amused" by the al-Qaeda leader's apparent words.
"I was not turned off by the endorsement," he told a New York radio station.
"I'm not repulsed and I am not going to pretend I am."
Mr Blum said there had been no threats against him since the endorsement.
He has described the 11 September 2001 attacks on New York and Washington as "an understandable retaliation against US foreign policy", but makes clear that this is not a justification of them.