For obvious reasons Tolstoy's thought on was are more relevant now than in 2016. One can summarize his position as "War is a useless waste of human life and goes against human nature. No rational person would ever engage in it". There I saved you reading the book
Tolstoy detests Napoleon and many of his passages on history serve to argue against the myth of "great man shaping history", which Napoleon represents. Throughout the book he tries to demystify him, points out how his genius is exaggerated, how much of it was luck and most of all argues against the idolisation of a man who committed many atrocities (He insists on calling him murderer). I want to put a quote here from the first epilogue:
In Africa a whole series of outrages are committed against the almost unarmed inhabitants. And the men who commit these crimes, especially their leader, assure themselves that this is admirable, this is glory—it resembles Caesar and Alexander the Great and is therefore good.
Kutuzov, the only good general in the Russian army.
In book two both Nikolai and Andrei get their first experience with war. Their expectations of adventure and glory respectively are contrasted with the reality of the pointless slaughter of human life that war is. Tolstoy is not subtle about his anti war sentiments. Both Nikolai and Andrei get loads of character development here, which the TV series completely fails at when it comes to Andrei. I still did not like him in the book, but at least he was interesting.
In the book Andrei's motivation is a quest for meaning and purpose and he thinks he can achieve that by chasing glory in the war. Before the first battle Andrei is riding around inspecting the preparations, making strategic plans and imagines winning the battle for Russia (as he always thinks he is better than everyone around him). Maybe while dying heroically for the glory. While he is still contemplating his brilliant plans the battle just starts and all is chaos. Here he just stands melancholic in a field for a minute and then the battle starts.
Nice cinematography, but some character development would have been cool. Andrei's character in the TV series is: Bored and might as well die in war... In love with Natasha... Depressed and might as well die in war.. Dies in war (spoiler).
During the battle he notices that the most successful generals are the ones that do not make great plans, but react to the actions of the man during battle. It is one of the first instances of Tolstoy's subversion of the idea of "great man of history". He focuses on Tushin (a captain), who is not concerned with glory or recognition (very short appearance in the TV series) and therefore is one of the deciding factors in the "victory" (They stop the French, giving themselves time to regroup, nothing more). He is shat on for it and Andrei comes to his defense. None of this in in the TV series.
When he goes to the Austrian court to announce the "victory" it is shrug off as unimportant. His great heroic moment thwarted from all sides. He is disillusioned with war and the army command, except Kutuzov. No one has a regard for the common soldiers or even cares if they win or loose and only tries to use any battle as a political play to advance their position.
Nikolai's part is much better. His naivete at the beginning, seeing was as a big adventure is shown very well. Jack Lowden plays him as excitedly nervous. I like his budding friendship with Denisov. I am very grateful they did not make the actor speak with the speech impediment Denisov had in the book, it was so annoying to read. When he finally is in the middle of the battle he absolutely panics. He throws his pistol at the French instead of firing it and then runs away. It is a very short scene in the TV series, but Jack Lowden nails it, not only showing shock and fear, but also confusion, as described in the book:
"Who are they? Why are they running? Can they be coming at me? And why? To kill me? Me whom everyone is so fond of?" He remembered his mother’s love for him, and his family’s, and his friends’, and the enemy’s intention to kill him seemed impossible.
Dolokhov is missing, though. He has a whole adventure, capturing some French in the book. It is alluded to by him being called a war hero in the series. I had to stop reading and laughed out loud when it turned out he is a sharpshooter.