What is your impression of the narrator?

Christopher is part of a long literary tradition of first-person narrators with unreliable or otherwise compromised ways of telling their story. Although Haddon's novel may seem new and unique in structure, it is also a modern example of a 20th century literary form.

Christopher is what was once known as an idiot-savant. He has difficulty with things that should be easy, like reading emotions, and finds easy things that should be difficult, like remembering exact details. It is a not uncommon psychological phenomenon that people with autism spectrum disorders and other developmental and cognitive disabilities will show extreme proficiency in one or more isolated skills. Christopher manifests a good deal of these savant characteristics, and his autism is mild enough to allow him to be extremely high functioning - these two characteristics combine to make him an excellent narrator.

He is not dissimilar in this way from his hero, Sherlock Holmes. Although Holmes is not a narrator (his stories are narrated by his colleague Dr. Watson), he is also extraordinarily gifted at isolated skills - and has a very hard time understanding emotions and interacting with people in a normal way. In the case of Holmes, the character is so brilliant that he can overcome his limitations through excellent acting and deduction of patterns, but one can see why Christopher so identifies with his fictional hero.