Book excerpt: An urgent, on-the-ground report from Pakistan—from the bestselling author of Descent Into Chaos and Taliban Ahmed Rashid, one of the world's leading experts on the social and political situations in Pakistan and Afghanistan, offers a highly anticipated update on the possibilities—and hazards—facing the United States after the death of Osama bin Laden and as Operation Enduring Freedom winds down. With the characteristic professionalism that has made him the preeminent independent journalist in Pakistan for three decades, Rashid asks the important questions and delivers informed insights about the future of U.S. relations with the troubled region. His most urgent book to date, Pakistan on the Brink is the third volume in a comprehensive series that is a call to action to our nation's leaders and an exposition of this conflict's impact on the security of the world.