Based on an outline of the milesstones and vicissitudes that marked the popes prior to Leon XIII, the circumstances that surrounded the promulgation of Rerum novarum in 1891 and the events and changes occurring during this century in different fields and inside the Church itself, Bishop George Pell rereads that document in which he notes that it must be considered in a context of global response to the secularization of the European spirit. He also emphasizes its enormous gravitation as well as how true the standards therein contain continue to be in judging the economic and social life of our times. Finally, Bishop Pell discusses the work and figure of John Paul II and explains the challenges that, in his opinion, the Church should now face both in western nations as well in developing countries of Latin America and the Third World.