An excerpt:

. . .The raid was the culmination of years of painstaking intelligence work, including the interrogation of C.I.A. detainees in secret prisons in Eastern Europe, where sometimes what was not said was as useful as what was. Intelligence agencies eavesdropped on telephone calls and e-mails of the courier’s Arab family in a Persian Gulf state and pored over satellite images of the compound in Abbottabad to determine a “pattern of life” that might decide whether the operation would be worth the risk.

As more than a dozen White House, intelligence and Pentagon officials described the operation on Monday, the past few weeks were a nerve-racking amalgamation of what-ifs and negative scenarios. “There wasn’t a meeting when someone didn’t mention ‘Black Hawk Down,’ ” a senior administration official said, referring to the disastrous 1993 battle in Somalia in which two American helicopters were shot down and some of their crew killed in action. The failed mission to rescue hostages in Iran in 1980 also loomed large.

Administration officials split over whether to launch the operation, whether to wait and continue monitoring until they were more sure that Bin Laden was really there, or whether to go for a less risky bombing assault. In the end, President Obama opted against a bombing that could do so much damage it might be uncertain whether Bin Laden was really hit and chose to send in commandos. A “fight your way out” option was built into the plan, with two helicopters following the two main assault copters as backup in case of trouble. . .