Full of mystery and romance, Black Jack is a suspenseful, action-filled story. Written in a descriptive style, the story includes authentic historical details that bring its eighteenth-century setting to life without ever becoming dull. Touches of ironic humor, aimed mostly at self-important people, enliven the story.

Garfield endows his many unusual, quirky characters with believable personalities, making them recognizable as real people. His depictions reveal a tolerance for human frailty and a belief in every person's potential for good. Nevertheless, his characters are complex, suggesting that there is often more to a person than appears on the surface.

Black Jack explores the often subtle differences between good and evil and shows how difficult it can be to tell them apart. The divisions between kindness and cruelty, love and hate, truth and hypocrisy, trust and jealousy, knowledge and ignorance can be murky as each of these qualities sometimes masquerades as its opposite.