Yesterday I finished reading Waterloo: The History of Four Days, Three Armies and Three Battles by Bernard Cornwell. This author has written many novels, of which I've read nearly all, and most of which I like very much, but I think this is the first piece of non-fiction I have read by him. I pushed to read this book at approximately this time due to the recent 200th anniversary of the battle. I was very pleased with Cornwell's writing on the subject; he combined background and personalities involved in a way that I'd never seen before in my reading about Waterloo, and the whole battle made far more sense to me because of it.
Excellent work. Very readable, even if you have no background on the Napoleonic Wars. Highly recommended!