Hehe well there was a lot of wars so you should be a bit more specific

In any case if you like samurais i recommend J. Clavell, Shogun, L. N. Tolstoys War & Peace is about Napoleons invasion of russia, most of T. Plieviers work is about 2nd world war from german point of view, H. Sienkiewicz wrote about swedish invasion of poland and its civil war in medieval times...
Thats just a few i rembered now.