The main theme at the center of the dark, Anglo-Irish play The Pillowman is the effects of parental abuse.
As the topic that drives the plot forward, main character Katurian K. Katurian has to face the memories of his disturbed and abused childhood at the hands of his parents. The effect of such abuse resulted in his works as a story teller of macabre children's stories. As a result, he now faces the abusive interrogation from the police of a totalitarian establishment regarding the sudden macabre murders of children from the area.
Aside from Katurian, his brother Michal is also a victim of abuse by his and Katurian's parents. Likewise, he also undergoes investigation and also shows signs of psychological distress. What is shocking, however is that Michal is indeed guilty of the children's murders, leaving Katurian with no other choice but to kill his brother in what looks like a much more merciful way to die.
Faced with the possibility of having his body of work destroyed if he does not confess, Katurian takes the risk and blames himself for the murders. This leads to the second theme of the play, which is the defense and preservation of art even under the pressure of a suppressive system. Katurian prefers to basically get himself murdered rather than give up his stories. McDonagh places special emphasis on the importance of this theme, bringing with it equal significance to the overall atmosphere and style of the play.