Otto Karrer, who has devoted much of his work to studying and promoting Christian unity, examines Oscar Cullmann's challenging theses concerning the primary of peter in the Church. The prominent Protestant theologian went further than others before him in recognizing the Catholic character of the early apostolic Church, but he retained the traditional Protestant view that Peter was only the primus of the early Church. Disputes over the position of the Roman Pontiff in the Church have traditionally centered upon the so-called primacy texts, especially Matthew 16:18 ("Thou art Peter. . ."). Cullmann in his peter: Disciple, Apostle, Martyr contended that no conclusions can be derived from that primacy concerning the apostolic succession and indeed the papacy as it developed. For him it is clear that Peter at an early date yielded his primacy to James the Less (whose position in the early Church has long intrigued scholars), and that the Catholic case for the apostolic succession is inadequately founded in the Scriptures. Cullmann's book was something of a landmark in theological controversy; it was free from any spirit of hostile polemic against the Catholic Church or the Papacy. The author hoped for some frank response from the Catholic side and it is here given by Father Karrer.