Black Jack tells of a boy's quest for personal identity and for a moral beacon to guide him through life. In Garfield's novels, journeys often symbolize moral quests. Tolly leaves the security of his uncle's home for the freedom of London and ends up with almost more freedom than he can handle when he travels with the unpredictable Black Jack, the eccentric members of the traveling fair, and the erratic Belle Carter. By the time Tolly returns to the safety of his uncle's ship, he has found his own identity and worked through his moral dilemmas: he has become an adult. His reunion with his uncle gives the story a circular structure, wherein the protagonist undergoes a series of developmental experiences but ultimately returns to the story's starting point.

Although Tolly provides the structure and purpose of the novel, he is not a particularly well-rounded character...