(New book from Popular Mechanics just released August 15, 2006) Introduction The first conspiracy theories about 9/11 began to emerge while the wreckage was still smoldering. As evidence accumulated that conclusively linked the hijackings to Al Qaeda, some self-proclaimed skeptics searched for alternative explanations. Many seemed driven to find a way to blame the United States for somehow abetting, or even orchestrating, the tragedy. In the years since the attacks, these assertions have grown progressively more lurid and pervasive. If you search the phrase “9/11 conspiracy” on the Internet, you will discover more than 800,000 Web pages. A few skeptics...