Ancillary Justice is a science fiction novel written by Ann Leckie. It takes place in a future where an empire called the Radch rules over multiple star systems. The story follows Breq, a former starship AI who seeks revenge against the ruler of the Radch. With its exploration of identity, gender, and power, Ancillary Justice has received critical acclaim and won numerous awards, including the Hugo, Nebula, and Arthur C. Clarke Awards.