Kong, 

    I understand your reaction to parts of Christopher's behavior; there is
  a pretty mysterious element to much of it.  On the other hand there are 
  also hints about what is going on in his mind that Mark Haddon is careful
  to include (by way of Christopher's first-person narration).  For instance,
  you say "Christopher’s emotions and his reactions to his emotions confuse me. 
  It does not make any sense to me why he would roll up and groan or mentally 
  shut down for hours."  I think you are referring specifically to Christopher's
  discovery of the letters from his mother.  But if you think about other
  episodes where he does similar things, you might see a pattern.  For instance,
  his difficulty in overstimulating environments (too many people, too much
  visual information flooding in on him, etc.) creates a similar reaction.
  Whenever he is in a situation where he feels overwhelmed, he rolls up on
  himself and groans to shut it out, the way any one of us might do in a
  situation that caused us extreme pain.  (Your ACL injury might not have
  been comparable; think of a compound fracture of a leg or some other 
  very serious and very painful injury.) In a really extreme situation, like
  the discovery of the letters, he shuts down completely for an extended 
  time.  

    You also point out that it seems strange that someone who is so talented
  at mathematics should have so little common sense (as indicated, for instance,
  when he chases his rat onto the subway tracks).  But I think you could say
  that what happens there might be similar to the way Christopher can focus
  on a mathematical problem when he's really engaged.  That's the one time
  where he really seems able to shut everything else out and concentrate.
  (This also connects with his attachment to Sherlock Holmes 
  It's not "smart" to do that, of course, but it fits with some of his other
  behavior.  And also, haven't most of us from time to time gotten so caught up 
  in something that we don't notice something important and do stupid things.  
  I know I have(!)

    My main point here is that while Christopher's behavior can seem 
  strange, a lot of it consists of reactions that most people might 
  have at some time.  But in him it is always taken to extremes.  That's 
  one way to start to understand him.  
  
  Some specific comments:

  (1) In your first sentence, using the commas to set off the "who seems to 
      have a different way of thinking" makes it kind of "choppy".  It 
      would be smoother if you rearranged things slightly:  "Mark Haddon’s 
      "the curious incident of the dog in the night-time" effectively conveys 
      the thoughts of a character who seems to have a different way of thinking."

  (2) On page 3: In "I definitely think there is and will always be borders ... ",
      the word borders is plural so the verb should be "are" not "is". 

  Content: 88 (B+)

  Mechanics: 92 (A-)