This is easily the best of the Best Related Works Hugo nominees. Burnside lays out what thermodynamics really mean for military actions and combat in space, at least if you are writing "hard" sf, intended to be based in scientific reality. That's not the only "right" kind of sf to write, but it's great when it's well done--and sad and frustrating when it's done badly. It's one thing to break the rules intentionally; another thing entirely to break them because you don't know you're doing it. As with any other rules, if you're going to break them, you should know you're doing it, and how, and why.