Almost a year after A.I.G.'s collapse, despite a tidal wave of outrage, there still has been no clear explanation of what toppled the insurance giant. The author decides to ask the people involved--the silent, shell-shocked traders of the A.I.G. Financial Products unit--and finds that the story may have a villain, whose reign of terror over 400 employees brought the company, the U.S. economy, and the global financial system to their knees.