Within the stories, Scalzi explores themes of maintenance of empire and control, in a populous and fractious galaxy, where freedom and self-determination may carry a real risk of subjugation or extermination by others.
What are the motivations and choices of the leaders of the Conclave, the Colonial Union and Earth, who are pressed from all sides by competing and often irreconcilable demands? ('This Hollow Union')
How do common soldiers cope when their orders to protect the staus quo of empire sees them participating in actions which seem against the interests of those they are tasked to protect? ('Can Long Endure').
It is all wrapped up nicely enough in the finale 'To Stand of Fall', which might well be the last we see of this particular series.
Scalzi's light hearted and mildly mocking prose reads and scans well, and the narratives in the individual stories motor along quite satisfactorily. To some extent, the exploits of our heroes are perhaps overly assisted by the stupidity or overconfidence of their enemies, but these faults are minor. Well worth the time to read, especially if you have enjoyed the earlier installments.
Not quite on my Hugo radar, notwithstanding Scalzi's expressed desire to recuse himself this year.