Beginning with the papacy of St. Peter, the author emphasizes that each pope is the successor of Peter, the "servant of the servants of God". Each picture he draws of these eleven significant pontiffs reveals not so much how each succeeded or failed in his role as servant, but to what degree each fulfilled that role, and how deeply each struggled to do so. He allows the circumstances of the era in which each pope lived to make the judgments on that particular pontificate. He very succinctly draws out the constant contrast between the human and the divine, the struggle to make real heaven's mandages on earth, emphasizing throughout his story the weight of the "heavy burden laid on all those who inherit the Lord's command to Peter."