I enjoyed this book. It is brief. I read it shortly after Roy Jenkins Life of Churchill.
Geoffrey Best wrote this book to satisfy his curiosity about Churchill's greatness, and the conclusion he draws (that Churchill was very great indeed) is persuasive. Best seems well-informed, and his judgement so far as it goes reliable.
But, I describe the book as "partial" because, being brief, it doesn't attempt to cover every detail. For example there is little detail about Churchill's government activity in the 1920s, little about his parliamentary campaigning, no mention of his holidays in Madeira, no mention of the delight he took in holidays near the Atlas Mountains. I think the quality, energy, and wide ranging contribution in government in the 1910s and 1920s was not only important in its own right, but an augury of the magnificent contribution he made in later years, ... and Best understates the inherent quality of these auguries. Just as Churchill said, it was as if all his former life was a preparation for the trials of the Second World War.
I found Bests Epilogue interesting. It discusses eg whether the values and worldview of Churchill (eg roughly nationalistic and pro-Anglo-Saxon management) can be understood and sympathised with these days. Best mentions Isaiah Berlin and Clement Attlee as two people who wrote penetrating essays about Churchill. I shall try to read both of them.