The last and most important theme in the text is difference. The author explores the idea of different through narrative voice, clues and crime. The protagonist is different from other typical protagonist because he had Aspergers. In society sometime people fear the difference. When people encounter with people who are different, they would likely to criticise and judge that person. However, through Christopher narrative voice the audience learned about him that he can be similar to a normal person. Haddon the author want to show readers that even with disability, the protagonist can still be able to do things that a normal person would do. Other conventions that Haddon had slightly changed to makes his story different are clues and crime.