Before and after: There are no photos of flight 77's impact
Thierry Meyssan's book L'Effroyable Imposture (The Appalling Fraud) alleges the attack on the building, which houses the US defence department, was staged by none other than the American Government.
Mr Meyssan's book alleges that eyewitness accounts of the crash are contradictory, photographs of the scene show no wreckage of an airliner and the damage to the building is inconsistent with an authentic air crash.
A related website, Hunt the Boeing, contains photographic evidence to back up Mr Meyssan's claims.
The site seems to favour the theory that "a booby-trapped truck caused the explosion" as the first reports, quickly denied by officials, had suggested.
But it does not attempt to explain why the attack on the Pentagon might have been fabricated or how the 68 people who perished on flight 77 died.
Brisk business
A Pentagon spokesman, Glen Flood, described the book as "a slap in the face and real offence to the American people, particularly to the memory of victims of the attacks".
But Mr Meyssan's provocative theories have proved irresistible to the French public.
"Copies have been flying off shelves," a saleswoman at Fnac bookshop in central Paris. "It's a phenomenon," said another.
Reports say the book's original run of 20,000 copies sold out within two hours of going on sale.
Fnac says its 2,500 copies sold in 10 days, compared with blockbuster novels which sell maybe 1,500 in a month.
The book is currently the top of Amazon France's bestseller list and has made it to second place in the Livres Hebdo's list.
'Confidence trick'
But French media reports have mocked Mr Meyssan - who is president of the respected left-leaning think tank Reseau Voltaire - and compared his book with the Roswell alien cover-up theory.
Liberation slammed the book as "a tissue of wild allegations".
"This phenomenon is not typical of the French," sociologist Pierre Lagrange told Liberation.
"But the events of 11 September gave us a reality so similar to science fiction, that there has been more of a market for paranoid interpretations."
News weekly Le Nouvel Observateur denounced the book as revisionism. "This theory suits everyone - there are no Islamic extremists... everyone is happy. It eliminates reality."
But while Le Monde joined in the attacks on the Meyssan book, it admitted that the whole truth about the flight 77 incident was yet to come out.
"There is no official account of the crash...the lack of information is feeding the rumour."