The principal theme of The Miracle of the Bells is individual transformation. Protagonist Bill Dunnigan starts out as a cynical, worldly press agent who prides himself on his ability to manipulate public opinion. The idealistic and luminous young Olga brings him out of himself, and he becomes eager to make life better for her. This leads to a quest to improve life also for Father Paul, then the citizens of Coaltown and others as well. Father Paul, introverted and discouraged, is also transformed into a courageous young priest unafraid of his parishioners and determined to succeed in bettering their lives.
As Bill spreads his goodwill and money around Coaltown, others are also transformed from enemies into allies by the power of love and fellowship. Father Spinsky, formerly greedy and uncharitable, responds to Bill’s love and becomes humble and eager to help Father Paul and others. Hard-nosed producer Marcus Harris learns to think of more than the bottom line. The police, union officials, beaten-down miners, the contemptuous mine owner, and even national political and entertainment stars catch the vision of Olga’s naïve yearning to help others and find enjoyment in working together to lift Coaltown and its citizens to a better life.
Along with the contagious nature of brotherly love, another theme of the novel is the eternal nature of the soul. Olga’s spirit survives after death, appearing to Bill and to her childlike former friend, Andrev, to give encouragement and inspiration. Father Spinsky is also spurred to reform by a vision of Olga’s dead father, an alcoholic who was turned away from St. Leo’s years before. Bill becomes convinced that Saint Michael, patron of Father Paul’s church, is helping him with his quest. Readers, however, are left to form their own conclusions about the miraculous turning of the Saint Michael’s statues to face Olga’s casket. While the settling of foundations over mine shafts is mentioned, the question is left open as to why it occurs at this particular time, in this particular way. The primary miracle referred to in the novel’s title, however, is what happens in the lives of individuals when they soften their hearts toward their fellows and learn the joy of good works.