In 2003, Dr. May was recruited to the 9/11 Commission by Philip Zelikow, whom Dr. May had encouraged to lead the commission. Zelikow, now a University of Virginia historian, had edited three volumes with Dr. May on John F. Kennedy's presidential tapes, starting in 1997. Their work formed the basis for the Hollywood film "Thirteen Days" (2000), starring Kevin Costner as an aide to Kennedy during the Cuban Missile Crisis.