These premises, which the prominent German Catholic philosopher Robert Spaemann has described as almost ridiculous (probably due to the fact that for years Küng, because of his relativist inclinations, has not been allowed to represent his original teaching subject, Catholic Dogmatics, within the Faculty of Catholic Theology), have resulted in three volumes of around one thousand pages each: one on the Jewish creed, another on the faith of Christians, and finally, in 2004, still another on Islam.
Like everything that Küng has published in recent years, the volume on Islam is both informative and wordy to an almost annoying degree. It describes in detail the history of the Muslim religion, analyses its various forms, and asks questions about a possible dialogue between Muslims, Jews and Christians.
Obviously, the three main problems in a dialogue with Muslims are the Christian Trinitarian creed, the divinity of the man Jesus, and the authenticity of the Koran.
As to the Koran, Küng suggests that Christians should not a priori reject the idea of a special divine revelation for the Arabs. As to the Christian faith in a God who is three persons and the creed that the man Jesus was the incarnation of the Divine Word, Küng recommends an approach that reminds us of the ideas of the 'Messianic Jews'.
What Christians believe today, Küng argues, is a synthesis of Jewish ideas with Greek
At the beginning, he suggests, the followers of Jesus recognised him as the foretold Messiah but still did not think in Trinitarian terms and had no clear idea what Jesus being more than a divine messenger meant.
All in all, Küng´s volume about Islam succumbs to the temptation that has always been the author's greatest weakness: in order to make the Christian creed acceptable to contemporaries, he rattles off as myth or mere philosophy substantial tenets of the Christian tradition.
This was already his problem at the time when the Bishop of Rottenburg followed the request of the Holy See and removed Küng from the Tübingen Faculty of Catholic Theology; the theologian was not willing to admit that it was a mistake not to mention in his writings on Christ the dogma that Jesus' person pre-existed as the divine Logos.
Some of his acquaintances believe that Küng's greatest fault is his pigheaded stubbornness.
That Benedict XVI received him in a private audience was certainly an admirable act of charity (after all, they both were aides of German Bishops during the Vatican Council) rather than a recognition of Küng´s theological merits.