Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Good Book for those already knowledgeable of the period.

John Lukacs book has an excellent premise; which is that the period of 1940 generally known as the Battle of Britain represented, for the leaders of Britain and Germany, a personal duel in which their ability to motivate and lead their respective governments were critical to the outcome. He makes his case very convincingly; while Britain would certainly have fought under a number of possible wartime PM's (Anthony Eden, perhaps, or Lord Halifax), the personal leadership provided by Churchill was critical to Britain's success.The book assumes a good working knowledge of the players involved and of the period; this is a good book for a World War II history buff, but is not intended to be a primer. This aspect of the book makes it difficult for novices; after having read Churchill's 5 volume history of the war and half a dozen other works, I understood the nuances of the book.