It's a somewhat older book, but it still gets the idea across. Check out War Is A Racket, by Smedley Butler. He was a Marine officer for many decades and fought in several conflicts in the Caribbean, China and the First World War. Later he exposed the Business Plot, and he was awarded the Medal of Honor twice. Butler is a very interesting and unique figure in US military history.

If you have the stomach for a rather dry but, highly informative book check out 'The Power Elite' by C.W. Mills