The Pontiff's power of reservation has existed for centuries: it began to develop in the Middle Ages as the papacy established itself as head of the medieval Church and the entire Christianity. This monograph is an analysis of the new system of papal reservations in relation to the Bishops as described in the 1983 Code of Canon Law and in the legal prescriptions of the Roman Catholic Church. The study highlights the cases which the Pontiff reserves to himself, removing them from the responsibility of the diocesan bishops, who continue to exercise the power they possess in their own right.