"What does it mean to be loyal to the Pope, if we do not consider ourselves obliged to know who the true Pope is?" "For the purpose of knowing who the true Pope is." This is what Benedict XVI: Pope "Emeritus"?, by the Master in Law of the University of Medellin, Estefanía Acosta, helps to answer, by addressing, in light of divine and ecclesiastical law, the still current (and greatest) impasse suffered by the Papacy at the gates of its bimillenial existence. A basilar and indispensable instrument for understanding Benedict XVI's declaration of resignation and Cardinal Jorge Mario Bergoglio's election, as well as their later developments, this work, the most complete study of canon law on the subject, has as one of its great merits that of helping so that, with Saint John Bosco, the cry Long live the Pope! may resound. Certainly, a hot topic, like our times, especially for all those who in spirit and truth are interested in God, the Church and the Papacy.