According to Paul, it is by the Spirit, through Christ, that God transforms people, communities, and the cosmos Prominent recent studies elevate the themes of "Christoformity" and "Cruciformity" in Paul, but few sufficiently account for how a believer is actually transformed into the image of Christ. Pneumaformity fills the gap in Pauline studies by surveying Paul's letters for teachings on the Spirit's agency in the life of God' people. This study aptly demonstrates that the Holy Spirit is the instrument through whom such radical living is possible. This study dives into Paul's teachings on the following aspects of the Spirit's agency and more: the Spirit's participation in conversion the Spirit's role in forming Christian character the Spirit's integrating work within the Christian community the Spirit and missional engagement the Spirit's place in the believer's final eschatological transformation Keown shows how Paul infuses his christological language with pneumatological realities, offering readers a fuller understanding of the Spirit's work in individuals, the church, and the world.