This is a wonderful book for the Introvert in your life. If that Introvert is _you_, consider getting two copies: one to read and one to share with friends, co-workers, and family members.
It's a light read, but well written and well organized. My favorite chapter, "Don't Call Us, We'll Call... Well, No, Maybe We Won't" describes many Introvert's love/hate relationship with phone calls. We may love the person on the other end of the line (Hi Mom!) but we hate communicating by telephone. (It may not just be Introverts who feel this way. According to Neilsen, in 2008 people were sending or receiving more texts on mobile "phones" than phone calls.)