"Castles of Steel" by Robert Massie. Story of the dreadnaughts and the RN's role, almost day to day in its details, during WW1. Very well written and incredibly well researched - and it might change your opinion about some of the things you think you know about some of the personalities of the time. (I learnt a few things about the Dardanelles campaign I wasn't aware of that give Churchill a softer ride than he gets in most histories of that campaign.)
I was surprised how contemporary it felt to me, particularly in regard to the politics of the day. (In short: just like today; nothing's changed!)