Ancillary Justice

Justice of Toren was destroyed, but the AI of the ship survives within what is known as an "ancillary" -- a human body sans everything that makes it human (memory, personality, soul), so that it exists only as a tool for the artificial intelligence. Ordinarily, there are hundreds (if not thousands) that exist at a time, but Justice of Toren is left with just the 1 individual.

Her adversary is the Lord of the Radch, Anaander Mianaai, who has split herself into multiple copies. This eventually leads to a division within herself and an inevitable civil war to come in the upcoming novels. So there is a very engaging contrast between the main characters -- one is a human who is losing her identity by virtue of multiple copies and bodies; the other is an AI gaining an identity after the loss of so much of what she was (ship, soldiers, crew, etc.)

Leckie takes full advantage of the unique type of narration possibilities that are opened up with this very clever scenario and the book is enjoyable to read on just that account. But it is also very good sci-fi with well drawn characters and -- as is true time after time with quality SF -- striking discourse on what is means to be human.