It's pretty widely known the USA's Pacific island hopping campaign was brutal stuff, but I didn't know how brutal until I read Sledge's With The Old Breed.
He takes an unflinching look at several island campaigns, where Marine units would fight for days to capture just a few hundred yards of rough, almost impassable ground.
I don't know how they did it. Hollywood certainly glamorized the fight for the Pacific, but this title (and a few others) quickly disabuse the reader of those notions. A good -- if occasionally uneven -- read.