This is a new, that is, corrected and updated, edition of a book first published in 1979. It has been recast in inclusive language. As a systematic treatment of the theology of grace, it concentrates on what may be termed the key question in this branch of theology, the person of Jesus as the arena where the full drama of the interaction of God and humanity is played out. The book breaks new ground in that it attacks the long-standing dichotomy between the Incarnation and grace, and offers a new principle of synthesisation. This principle is that the Holy Spirit is Spirit of Sonship primarily for Jesus himself, so that it is the creative outpouring of the Spirit on him by the Father that brings about the Incarnation. The Spirit is seen as the Spirit of filiation for others only in function of his role in relation to Jesus. A more profound interpretation of the patristic expression ""sons and daughters in the Son"" emerges from this study. While the book is situated in the Catholic tradition, its ecumenical implications are manifold.