In recent years, the canonical legal order and the Vatican legal order—distinct from one another yet closely interconnected—have been confronted with unprecedented challenges. These challenges, however, do not originate from external sources but arise from within their own boundaries. Within both the Church and Vatican City State, certain recent normative developments in the field of penal law, both substantive and procedural, together with certain practices adopted—particularly in judicial proceedings that have attracted worldwide attention, such as the ongoing case concerning the prosecution of Cardinal Becciu—appear to disregard, and thus place in jeopardy, the fundamental principle of due process and its corollaries. These are principles that enjoy universal recognition and which, in the canonical order—and hence also in the Vatican order, where canon law constitutes the primary source of law and the primary criterion of interpretation—are rooted in the ius divinum, which is absolutely inviolable. It is, therefore, urgent to examine the implications of violating these principles. As the present volume seeks to demonstrate, the consequences are not only grave and disruptive within the Church and the Vatican, but also extend beyond their confines, having serious repercussions on relations with secular legal systems.