What is he really like? Bombastic, autocratic, say his critics. Colourful, stimulating, say his admirers.
Tim Heald was given a unique opportunity to find out for himself. Not for twenty years had a biographer been allowed such access to talk to Prince Philip and watch him at work - still very much a man in a hurry, still speaking and questioning on an astonishing variety of subjects and treading the most impossible tightrope between the breezy informality which he first introduced to the royal family and the parade-ground traditions which he has had to accept.
And members of the royal family - among them the Queen Mother, Princes Margaret, Princess Anne and his only surviving sister, Princess Sophie - also share with Heald their thoughts on the man who started life as Philip of Greece, one of a royal family who were deposed and exiled while he was still an infant.
Many other witnesses reveal for the first time the Prince Philip they know. His early days in exile, at schools in France, in England and in Germany - where he had first-hand experience of the 'unpleasant habits' of the Nazis, and then in Scotland at the newly founded Gordonstoun. His service with distinction in the Royal Navy during World War Two. His engagement in 1947 to Princess Elizabeth, twenty-one-year-old daughter of King George VI.
As TIm Heald observes, Prince Philip swiftly emerged as very much his own man, winning over one or two doubters within the Court who might have preferred a home-grown aristocrat as husband to the future Queen.
Written with the co-operation of Buckingham Palace, THE DUKE is a brilliantly informed portrait of a life that has been independent of, but fully supportive to the Queen.