New Delhi, Sept. 23 -- Charles Spencer had planned to let the book speak for itself. By the morning it went on sale, the king had already made that impossible.

Diana, My Sister," Spencer's account of his sister's life and death, a rare move from an institution that prides itself on staying above such disputes. The statement read: "While we do not comment on books as a matter of principle, His Majesty is mindful that the pain of fraternal grief can cloud reason, affect judgment and color memory in ways others do not recognize, even many years after such a loss." King Charles has not addressed the book's specific allegations directly.

Spencer's response, posted online within hours, became an instant headline. "It is not every day you wake...