What is the best book you've read about the military?

We Were Soldiers Once… And Young by Lt. Gen. Harold G. Moore (Ret.) and war journalist Joseph L. Galloway

Great book

Lone Survivor. I read it before the movie was made, which wasn't nearly as good as the book.

I read everything I could find about the Civil War until my wife began bringing me diaries that she found. One written by a Confederate chaplain and another written by a Confederate officer who served on the staff in Richmond after being wounded in battle. Thereafter, I was hooked on reading the words of those who lived the war. Most recently I finished reading The Somme: The Darkest Hour on the Western Front by Peter Hart. This book is filled with quotes from letters and diaries of those who fought the battle, glued together with just enough narrative to provide context. I wish more authors would use this technique. I tried in my book about Castro's revolution in Cuba, but sadly most of the participants were illiterate and the few writings left by the principle actors such as Castro and Che were little more than blatant propaganda. Still, I used their own words from speeches to provide dialog and common sense and infantry training to speculate on the battles from the little evidence available.