I'm reasonably sure I've read all the "Old Man's War" books. As the last one was published a decade ago, you'll forgive me if I don't remember all the intricacies of galactic politics and interpersonal intrigue. Thankfully, Scalzi has carved off a side character from a previous book and given them a brand-new adventure. There's enough exposition to tickle the parts of your brain that go "Ah,…