Who is Jem Finch in the book To Kill a Mockingbird by Harper Lee?

Jeremy Atticus "Jem" Finch - Scout's brother and constant playmate at the beginning of the story. Jem is something of a typical American boy, refusing to back down from dares and fantasizing about playing football. Four years older than Scout, he gradually separates himself from her games, but he remains her close companion and protector throughout the novel. Jem moves into adolescence during the story, and his ideals are shaken badly by the evil and injustice that he perceives during the trial of Tom Robinson.