No one knew more about Marilyn Monroe's shattered dreams of escape to the magic of Camelot than Pete Lawford. He had introduced the excruciatingly fragile star to the high-stakes world of his brother-in-law Jack Kennedy and witnessed the crash ending of her much more serious affair with Bobby Kennedy—on the last day of her life. But why did Lawford ignore her final plea for help? JAMES SPADA reports in an excerpt from his new biography