Steven Pressfield's THE AFGHAN CAMPAIGN is my current read.
It's about Alexander the Great's 3 yr struggle to subdue the tribes, so he would have a secure supply route when invading India.

It's particually interesting at the moment, because my EB campaign as the Seluekids means I am fighting in this territory.

It brings to life the Mod so much more when you read about the remoteness of the place, and just reading the names of the places, and then finding them on EB's map. It makes more sense when it takes me ages to get troops through the 'wilderness'.