Goodbye to all that - Robert Graves
Another yes to this one. Period detail and attitudes. The casual humour of the trenches. How the old boys network and the class system work.
I've pre-read these for you so you don't waste your time. Am through with fiction for a bit so these are mainly non-fiction - especially history and science (both with the "popular" prefix ie. not too hard). PLEASE MAKE SUGGESTIONS IN THE COMMENT BOX!!