We speak with Craig Unger, author of the new book, "House of Bush, House of Saud" that details the complex negotiations on war, oil, illegal arms deals and murky banking deals conducted between the Bushes and the Saudis–connecting a US presidential dynasty to a foreign power. [Includes transcript]

Click here to read transcript In the days after the September 11th attacks, former Vice President Al Gore was grounded, former President Bill Clinton was grounded, planes were forced down in mid-flight, including one carrying a heart to be transplanted to a deathly-ill cardiac patient.

American skies were empty, yet at the same time 140 influential Saudis were effectively chaperoned out of the country–allegedly by the U.S. government. Among them, were several dozen members of the bin Laden family. They were never questioned by the FBI.

Despite the fact that 15 of the 19 hijackers were from Saudi Arabia, top White House officials approved the evacuation of Saudi citizens at a time when all other planes were grounded.

How was this possible?

The answer lies in the long-term relationship between the Bush family and the Saudi royal family that dates back over two decades and the is the subject of a new book by Craig Unger entitled, "House of Bush, House of Saud: The Secret Relationship Between the World’s Two Most Powerful Dynasties."

• Craig Unger, author of "House of Bush, House of Saud: The Secret Relationship Between the World’s Two Most Powerful Dynasties." He was deputy editor of the New York Observer and editor in chief of Boston Magazine. He has written about George H.W. Bush and George W. Bush for the New Yorker, Esquire and Vanity Fair.