G. K. Chesterton 
The Ball and the Cross (Centaur Classics) 

The plot of ‘The Ball and the Cross’ chronicles a hot dispute between two Scotsmen, one a devout but naive Roman Catholic, the other a zealous but naive atheist. Their fanatically held opinions—leading to a duel that is proposed but never fought—inspire a host of comic adventures whose allegorical levels vigorously explore the debate between theism and atheism.