Ancillary Justice is a well-crafted book with nice, slow reveals. I was satisfied by how Leckie merged two initially confusing storylines towards the second half of the book. Some scenes especially stuck with me, like Awn's interactions with the Lord of the Radch, throwing emotional fuel onto my pre-existing distaste for military/corporate hierarchies. I especially liked how she handled the mechanics of ancillaries interacting with themselves. For example:

My bodies sweated under my uniform jackets. And bored, I opened three of my mouths in close proximity of the temple plaza and sang with those three voices.

By framing the story through an alien lens, Leckie bypasses typical moralizing. She instead uses the mechanics of ancillaries to build a brilliant thought experiment on control and fragmentation at different scales.

Ancillary thought experiments

As in Iain Banks' Culture Series (e.g. Player of Games and Consider Phlebas and Use of Weapons), superintelligent spaceships figure prominently. In Leckie's universe, however, these ships are major characters, commanding armies of ancillaries, human bodies that are directly controlled by these powerful AIs. A single AI ship mind typically runs both the vessel and all of its ancillary crew. 

Ancillaries are ostensibly controlled by a single central superintelligence, but much of the drama in this universe happens when this assumption is violated. What happens when ancillary systems are jammed, forcing each individual back into autonomous mode? What happens when an individual in an ancillary system begins to diverge from the rest? What happens if there's a rift within an ancillary system? And, critically, do ancillaries still retain some of the individuality that was present in their original human owner?

Leckie uses this ancillary system architecture to make broader observations about our world from the vantage point of a very exotic environment. Ancillary systems sit at an interesting scale, containing tens to thousands of different individual ancillaries; straddling the gap between a single individual and a country. The same mechanics of control, fragmentation, and growth can happen at many scales: the micro scale (one human mind), the meso scale (the ship and its ancillaries), and the macro scale (the empire).

The Lord of the Radch is herself an ancillary system. Because a single mind controls thousands of her bodies, she can personally micromanage the empire. She is simultaneously the absolute monarch and the entire upper echelon of elites.

Yet The Lord of the Radch is an ancillary system literally at war with herself. This physical and mental division between her expansionist, imperialist half and her reformist, "degrowth" half is a macro-level reflection of the divided self. It serves as a parable for extreme political polarization where a single entity (a nation) turns against its own survival. Or, on an individual scale, it resembles a person experiencing conflicting desires. A lot of these themes remind me of Blindsight by Peter Watts, especially "The Gang" which is one physical body controlled by four different persons in sequence.

Phenomenon	Individual (micro)	Ship system (meso)	Empire (macro)
Division	Cognitive dissonance; conflicting desires; being "of two minds" on an issue.	A ship's network being jammed; ancillaries breaking from the core AI's control.	Civil war; political polarization; the Lord of the Radch literally split into two opposing factions.
Internal Communication	Internal monologue; talking to oneself; wrestling with a decision.	Ancillaries fencing or playing board games with one another; multiple bodies singing in unison.	State propaganda; inter-agency memos; the ruling class negotiating with itself.
Growth & Assimilation	Learning; adopting new habits or beliefs; neuroplasticity.	Capturing humans, wiping their minds, and converting their bodies into physical extensions of the ship AI.	Annexation; conquering planets, crushing dissent, and installing a feudal Radchaai culture.
Hierarchy & Control	Executive function overriding base impulses	The Ship AI puppet-mastering its ancillaries	The rigid command-and-control military structure

Thanks to BS and KD for their recommendations. Excited to discuss this book in the Campania book club reboot!