The history of the Second Vatican Council and the history of the policy of openness towards the East-Central European Communist countries, that is, the so called Vatican “Ostpolitik,” were looked at until now as two separate topics of research. The virtue of András Fejérdy’s work is to demonstrate, at the end of a thorough-going study through various available archives (first of all of the party and state, but also ecclesiastical ones), that it is not like that, but in reality the two topics are closely linked. Analyzing the history of the Hungarian presence at Vatican II in the context of the Hungarian Church policy and the evolution of the relations between the Holy See and Hungary, the book reveals that in consequence of the interests of the Holy See and the Hungarian party-state related to the Council—from the perspective of Hungary—Vatican II was not primarily an ecclesial event, but it remained closely joined to the negotiations between the Holy See and Hungary. During the Council, Hungary became the experimental laboratory of the Vatican’s new eastern policy.