Jonathan Strange and Mr Norrell is ultimately a story about the consequences of the misuse of power in various forms. Mr. Norrell and Jonathan Strange have magical power, but their approach to wielding it has significant negative consequences for them and those around them. For example, Norrell’s refusal to share access to his magical library allows him to maintain power (for a time) through the hoarding of knowledge. However, despite his facility with magic, his influence in the world is limited by his inability to understand when to wield social power rather than magical power, and the rupture of his relationship with Jonathan Strange and everything that follows are in part his fault.

Strange’s magical power contrasts sharply with Norrell’s, for his innate powers of magical improvisation allow him to successfully use magic to advance his ambitions, especially when he fights alongside Wellington and secures government contracts. Strange feels thwarted in his ambitions because Norrell wants to maintain the power imbalance that keeps Strange in a subordinate role long after Strange has outgrown their initial teacher-pupil relationship. Once freed of Norrell, Strange shows no restraint in exercising his magical powers, leading to the loss of his wife and his imprisonment in the pillar of darkness.