In his first interview about his new book, "Swan Song: Diana, My Sister," Charles Spencer talks with correspondent Mark Phillips about his attempt to set down what he calls the true history of the life of his sister, Princess Diana. He also talks about Prince Harry's grief after Diana's death, suggesting that a "more understanding treatment" of the young prince at the time might have led to "a happier course ahead." #PrincessDiana #CharlesSpencer #Royals #Diana #PrinceHarry