A Question of Blood by Ian Rankin is a crime thriller featuring detective John Rebus, who is investigating a shooting at a private school in Edinburgh, Scotland. The prime suspect is a former soldier, who is found dead shortly after the shooting, along with a teenage boy who had been attending the school. As Rebus delves deeper into the investigation, he uncovers a web of secrets and betrayals that suggest that the shooting may have been motivated by revenge rather than a random act of violence. Along the way, Rebus must confront his own demons and grapple with the complexities of justice and morality. The novel is known for its gritty realism, complex characters, and intricate plot, and is part of a popular series featuring John Rebus.