This study examines the participation of blessed Idelfonso Schuster in the Italian Liturgical Movement, and particularly in the recovery and usage of the concept of Christian Initiation. The study elaborates a presentation of his vast liturgical work, with a proposal of orderly classification of ordination: historical, pastoral and legal work. The unitary exposition of the Christian Initiation was new at that moment. He gets to this concept from historical data, examines it in its relation with Paschal Mystery (the central subject of his liturgical reflection) and develops it from his spiritual view of Liturgy (initiation to the divine life here and now). Pastoral dimension --continuous throughout his work-- grants to his reflections on the Initiation some concrete implications in his episcopal guidance: he recovers the leadership of the parish in the Christian life of the faithful and spiritualizes the meaning of Initiation in order to the edification and growth of the life of grace. In this scope, he develops a spirituality based in the sacraments of Initiation starting with Baptism, which justifies the Christian vocation to holiness, leading him to relive Christ, and ending with the Eucharist, genuine «soul and center of Catholic Liturgy». Schuster highlights the continuity of the Christian Initiation with the revelation of the Old Testament, and notices the formal evolution of the initiatory ritual process as a natural expression of organic development proper to Liturgy, without causing a rupture in its dogmatic character. [ABSTRACT FROM AUTHOR]