This book surprised me by being much better than I was expecting.
The blurb sells it as a bog-standard story of heroic spaceman versus evil killer robot, which, to an extent, it is, but it's also a great deal more than that.
Remainder of review under a cut, as there will be huge spoilers.
At first it seems obvious that the title refers to the robot, which is initially shown as a motiveless killer pursued by our hero in order to protect the galaxy from it. But as we learn more about the repressive imperialistic regime which produced both the human Captain Tracy and the robot itself, through a series of flashbacks, it becomes clear that the title could apply equally to the robot, the man and to the system he serves. And gradually, as the reader comes to this realisation, so does Captain Tracy, and it is this that shapes the final resolution of the story.
Excellent book, probably one of the best so far this year.