History is an inexorable process that which man cannot influence.
The existence of free will is questioned by the author. As he narrates the story of Napoleon's invasion of Russia, he illustrates how the (his)story takes twists and turns making the emperors silent spectators. If Napoleon Bonaparte was a mighty emperor why did he lose the battle against the Russians? A trivial cause like, he(Napoleon) catching cold just before one of the strategically important battles could be one of the possible reasons for his failure. And that happened without anybody but history's influence. If such a noble warrior could not influence history what to say of the common man?
'nyet' on #atheists once asked me why I chose the IRC Nickname after a dead man. If you didn't know, my IRC nick name used to be Bonaparte. And I replied, that I just am and quoted Tolstoy's deterministic world view.
History is not just the past. But it is an on going process which never stops. We think that we can influence it, but it happens on its own. So says the author indirectly.
Helen Bezukhova, Pierre, Natasha Rostova and Count Rostopchin are the characters that come to my mind when I talk or hear about the book. The narration is simply superb.