This volume is the result of a workshop organized in Leuven within the context of the Australian Catholic University-KU Leuven-Tilburg University project on Vatican II (1962-1965). This volume focuses on the preparatory period of the Council and its broader context, for many renewal movements were underway decades before the Council's opening. The preparation of the Council was also a period of intense consultation of bishops and male superiors of religious orders and congregations. Indeed, John XXIII aimed at introducing an aggiornamento into the Roman Catholic Church, taking into account the wishes and the needs of bishops and superiors. The volume presented here offers new insights about this period on the basis of archives and other materials insufficiently consulted to date. The papers presented are the result of research by both senior scholars and junior researchers. They focus on the following issues: revelation, ecclesiology, ecumenism, and education.