A Monster Calls is written for ages 12 and up, and although it is classified as a novel for middle school-aged children, the topics of mortality and the grieving process are universal ideas that are not specific to any one age group. Conor’s parents try to shield him from the ugly reality of death because he is young and they don’t want him to have to think about such disturbing ideas. However, as Ness demonstrates, encouraging denial when a person is facing a tough truth can make the process even harder by giving them a distorted perception of reality.

Conor refuses to talk to his grandmother about coming to live with her, because to do so would require thinking about a world without his mother in it. Conor is furious that his grandmother and father want to talk about life after his mother’s death, and he insists that the treatments are working. Conor’s grandmother even confronts his father, saying “she doesn’t think [Conor’s dad] or [his] mum have been honest enough with [Conor]. About what’s really happening” (134). When Conor insists that they are wrong and the yew tree treatment is going to work, his father tries to tell him that “Stories don’t always have happy endings” (134).