The last seven words in Michael Herr’s bestseller Dispatches lament: “Vietnam, Vietnam, Vietnam, we’ve all been there.” Well, yes and no. In Wayne Karlin’s most recent book Wandering Souls, the College of Southern Maryland teacher and Marine Corps Viet Nam veteran shows us finely detailed frames of what most of us never knew about that war — while reminding us what we perhaps have always known about that war. Or any war. War’s slogging nature is one of...