Jake and Lily by Jerry Spinelli

This book is about twins (Jake and Lily) who have been best friends since the day they were born. They have a sort of telepathic power  which they call their Goombla. For example, every birthday they have they both sleepwalk to the train  station and have the same dream. Stuff like that basically. As I said before they are ALWAYS together. ALWAYS. Until one summer... Jake joins a gang of boys after being bribed with cool rocks by Bump, a boy who has always been mean to Lily. When Jake joins the new gang Lily is left alone and is bored and heartbroken . She feels like Jake has dumped her. Jake meanwhile, has no trouble joining the gang and does not feel much remorse. The gang makes fun of and laughs at people they label “goobers” and they have no intention of letting a spunky, silly, burpy, crazy  girl join their gang. Encouraged by her grandfather Lily tries to build herself a life of her own, one that doesn’t depend on Jake, while Jake tries to distinguish the difference between right and wrong.

6th grade