What is the author's tone in Look Me in the Eye: My Life with Asperger's by John Elder Robison?

The author aptly conveys the confusion and frustration that he felt when he wasn't chosen for a sports team and when the other kids in general just steered clear of him. The reader can certainly empathize with the loneliness he felt and recognize how his self-worth must have taken a battering during those times. There is no tone of bitterness detected in Robison's words. He tells his story in an open manner and demonstrates his maturity and subsequent healthy development as he reflects on the most difficult days with understanding and a proper perspective.