Ancillary Justice is a science fiction novel by the American writer Ann Leckie, published in 2013. It is Leckie's debut novel and the first in her "Imperial Radch" space opera trilogy, followed by Ancillary Sword (2014) and Ancillary Mercy (2015). The novel follows Breq, the sole survivor of a starship destroyed by treachery and the vessel of that ship's artificial consciousness, as she seeks revenge against the ruler of her civilization. Two short stories by Leckie, "Night's Slow Poison" and "She Commands Me and I Obey", are set in the same fictional universe.