The origin of this book is an extensive votum presented, in 1966, to the Consultors of the Pontifical Commission for the Revision of the Code of Canon Law […] to examine for the first time the possible text of the canons on the rights and duties of the lay faithful in the Church […]. In that opinion, which was to have a decisive influence on the preparation of the project for the new ecclesiastical legislation, del Portillo grappled resolutely with a problem which had been very much at the fore in the work of the recently-concluded Second Vatican Council: that of the theological-canonical meaning of two concepts—faithful and lay person—which were often used interchangeably in ecclesiastical parlance but which differed from each other from an ontological perspective. Álvaro del Portillo […] pondered over the question: Is the baptismal spirituality sufficient on its own to define the identity and mission of the “lay faithful” in the Church? Is the lay faithful to be identified with the generic concept of “Christian,” christifidelis? For himit was obvious that all the members of the Church—including clerics and religious—were Christians, baptized, faithful; hence it seemed to him to be necessary to go deeper and to distinguish, as the Council had done, between the generic concept of “faithful” and the specific concept of “lay faithful.”This would also be relevant when the time came to draft the canons on their respective rights and duties. Thus in […] making the appropriate distinction between the possible canonical status of the “faithful” and that of the “laity,” del Portillo had very much in mind the ecclesiology of Vatican II and especially the Constitution Lumen gentium, which considered “secularity”—a concept very different from and even opposed to that of the “secularization” of sacred persons or things—as a specific theological component of the identity of the lay Christian: “What specifically characterizes the laity is their secular nature. … [T]he laity, by their very vocation, seek the kingdom of God by engaging in temporal affairs and by ordering them according to the plan of God. They live in the world, that is, in each and all of the secular professions and occupations” (Lumen gentium, 31). TheAuthor […] stated in no uncertain terms that lay Christians who are in full ecclesiastical communion have all the rights and duties that correspond to them as “faithful,” but it was also necessary to specify certain rights and duties that pertain to them as “lay faithful.” It comes as no surprise therefore that that weighty and extensive votum should have had such an impact on the definitive formulation of the canons on the faithful and the laity, both in the current Code of Canon Law promulgated in 1983, and indirectly in the later Code of Canons of the Eastern Churches promulgated in 1990.