 Inspired by the author 's participation in the Allied bombing of the monastery at Monte Cassino during World War II , the novel is considered a masterpiece by literary critics . It has been compared favorably with the works of Evelyn Waugh , Graham Greene , and Walker Percy , and its themes of religion , recurrence , and church versus state have generated a significant body of scholarly research . Miller 's follow @-@ up work , Saint Leibowitz and the Wild Horse Woman , was published posthumously in 1997 . 
