PRINCESS MARGARET by Nigel Dempster Macmillan; 242 pages; $11.95
"One is used as a figurehead .. . and the sister of you-know-who." The weary speaker is H.R.H. Princess Margaret, royal subject of this most common volume, currently a sensation in Britain. It is not difficult to see why.
According to Nigel Dempster's keyhole narrative, the figurehead has lived "a life unfulfilled." Whether she might have been happier as Prime Minister or nanny is unspecified; certainly she could have had a more gratifying Boswell. Dempster, 40, is a gossip columnist for the London Daily...