Throughout the 20th century, American corporations were governed by autocratic, almost unaccountable chief executives. Their word was law and the only check on their power was a board of directors composed of their friends and allies.

Then, in a stunning reversal, a momentous series of firings deposed the heads of some of the world's best-known companies: AIG, Morgan Stanley, Boeing, Hewlett-Packard and Pfizer, just to name a few. Formerly unchallenged CEOs found themselves under fire, often from their own handpicked boards. The number of deposed executives is astonishing. In 2004, the leaders of 600 companies were asked to leave. That numbers more than doubled in 2005 and reached 1,400 companies in 2006.