This is the kind of book that you'd want to read slowly. It's a small book, and it is written in the format of letters sent from the protagonist to a friend, so it is easy to want to move fast, but believe me, the beauty of the book is in the detail. 
 Charlie is a brilliant, thoughtful and insightful individual. As he enters high school, where a lot of price is put on being social, he finds it challenging because he is an introvert. He writes brilliantly about his observations and feelings, but he has trouble expressing it. 
 As the book progresses, he becomes friendly with some seniors of his, who understand his uniqueness. The new friendships, love, dating experiences and relationship dynamics bring charlie to a world he only has read about so far. 
 Towards the end of the book, a huge mystery considering his past is resolved, and he faces the consequence as well as relief of it. 
 Overall, I would say that the book handles being different from others in a very beautiful, delightful way, and normalizes the fact that being different need not be a drawback. A very fulfilling journey.