n the turbulent hours following President John F. Kennedy’s assassination, many were uncertain about what to do, but medical examiner Earl Rose knew one thing: The shooting happened in Dallas, and it was his job to do an autopsy on anyone slain in the city. Rose stood in a doorway at the hospital where Kennedy’s body was taken on Nov. 22, 1963, in a vain attempt to block Kennedy’s aides as they removed his coffin. The Secret Service and first lady Jacqueline Kennedy prevailed, and the president’s body was flown to Bethesda Naval Hospital, where an autopsy was done by...