What is the theme in Winston Churchill: A Penguin Life by John Keegan?

Ambition is a crucial theme of the first half of Winston Churchill: A Penguin Life is that Winston Churchill is a man who loves power and has great ambitions to rise to great prominence. Each step in his life is clearly a stepping stone to the next as soon as he becomes socially, academically and politically aware early in his adult life. Serving in war gives him a sense of physical and emotional courage and a natural hatred of tyranny drives him to buck all the authorities he knows, and later all the dictators he encounters. Many people deride Churchill's obvious drive to rule, including M.P.s, who often find him insufferable. Churchill even loses a serious love interest over his love of fame.