She signed simply "Diana," gracefully easing the blue marker along the white of her blouse in this magazine photo. Just the first name is necessary. Her charm, charity and station as would-be queen made that possible. In a visit to St. Louis before her 1997 death, Princess Diana gave the autograph of a lifetime for any collector to a noted Chicago newspaperman. For Anglophiles, it is more precious than that. Comes with his letter of authenticity, a breathtaking remnant of a royal who never lost the common touch.