The concept and practice of active participation in the liturgy grew with the twentieth century. It began with the recovery and analysis of ancient liturgical forms in the late nineteenth century and climaxed in reforms following Vatican Council II and their implementation. Eastern theological influence was clear in the notion of theiosis (divinization), tamed in the West to “sanctifying grace,” and that divinization was clearly trinitarian. Pivarnik’s ultimate purpose is to show liturgical participation as entrance into the trinitarian Mystery.

Pivarnik sets the context in his first two chapters. These examine the search for meaning in liturgical participation and its unfolding dynamic trinitarian reality (“narrative”) of Church. The narrative of Trinity, the self-communication of the triune God to humanity, proves to be the unifying meaning of various forms of participation—metaphysical, soteriological, ecclesiological, and eschatological. Thus, liturgical participation is participation in the Church’s deepest reality, the Divine.

Pivanik traces developments in the thinking of Pope Pius X (first magisterial use of the term), Vatican Council II, and postconciliar figures. For Pius X active participation restores all things in Christ, and that became the basis of the liturgical movement that reformed Catholic worship. Pius XII’s Mystici Corporis (1941) and Mediator Dei (1947) have participation as a central consideration, with a priestly character flowing from baptism. Interpretative responses varied, but motifs emerged: Mystical Body, theology of laity, human suffering, and a noncommunitarian Christ-centered approach that keeps participation from being solely human. These are central to the teaching of Vatican Council II.

In the second part of the monograph Pivarnik explores the thinking of Vagaggini and Kilmartin for explaining the trinitarian character of sacramental action and sacramental participation. Vagaggini began his work just before the Council and Kilmartin became prominent in the decades following. For Vagaggini, the bodily character of liturgical signs, sacramental and incarnational, in revealing the Paschal Mystery of the Lord is central to liturgical experience. Kilmartin starts with early Eucharistic Prayers at a covenantal sacrificial meal. For him, sanctification in worship is the action of Christ and Church, the self-communication of the Trinity received in faith. Kilmartin thus emphasizes conforming to Christ through participation in his Mystery-Presence, the Spirit’s work and mission.

The third part analyzes Vagaggini and Kilmartin’s scholarship from critical focal points: use of sources, consistency with the trinitarian tradition, and maintaining participation. He notes developments in magisterial teaching and theological reflection.

Pivarnik ultimately presents an intellectual framework for entering the trinitarian Mystery. Key elements that he adds to previous studies are a baptismal focus, the experience of trinitarian relations through the Persons’ active presence, and sacramental ethics as an extension into the Eschaton. These he convincingly presents as central to creating a new liturgical language based on experience. He states this succinctly as “decidedly trinitarian,” confirming “that the grammar of salvation history is presented in the liturgical action that moves believers from this life into the eternal life of the triune God” (p. xxiii). Transformation in grace, entrance into the divine life of the Trinity, requires full, conscious, and active participation in the liturgy.

This is a thoroughly scholarly and readable study. Its riches are densely packed but both accessible and stimulating. I strongly recommend it.