Six years after publication of the first edition of the best-selling Encyclopedia of Terrorism, much has changed on the national security scene. Despite the dark promises of Osama bin Laden following the 9/11 attacks, the United States has not experienced any major domestic terror incidents. Al-Qaeda itself is believed to be a severely crippled organization. But while U.S. wars in Afghanistan and Iraq--not to mention the arrival of the Obama administration, a new balance of power within...