The Ball and the Cross Novel by G. K. Chesterton "The Classic Annotated Edition"

"The Ball and The Cross" is the story of conflict that arises between an ardent Roman Catholic and a militant atheist shopkeeper when the Roman Catholic becomes enraged by a blasphemous display in the latter's shop window. The two get into a scuffle and after being hauled away by the police agree to a duel. As they search the city for the perfect place to duel, they meet numerous interesting characters that persistently interrupt their attempts to duel and, in the process, come to a realization that they have more in common than they first thought. "The Ball and The Cross", G. K. Chesterton's second novel, is a humorous and satirical look at the conflict between disparate philosophical and religious beliefs.