What is the author's tone in Winston Churchill: A Penguin Life by John Keegan?

The tone of Winston Churchill: A Penguin Life combines the historical and the adulatory. John Keegan is a British military historian who is a great admirer of British history, having written about it extensively. He clearly regards Churchill highly and it comes through in the text. This is particularly clear in the first chapter when Keegan describes how as he is coming of age politically, he and his generation see Churchill as a Conservative reactionary but that once he gets a more American perspective on Churchill he is able to break out of his ideological shell and appreciate Churchill for the great man that he is. The tone at this stage in the book is highly positive, particularly when Keegan describes being "electrified" by Churchill's speeches.