Testimonials to Experience of the Trinity is a study in spirituality of the Trinity. 'Testimonial' refers to an affirming witness to experience of the Trinity offered with the intention of encouraging such experience or openness to it. This approach through testimonials provides access to experiences of the Trinity and the varying forms they take. After an initial chapter on Jesus as Spirit-empowered son of Abba, the study presents 15 testimonials to experience of the Trinity. They represent four periods in the history of Christianity in its worldwide expansion and exemplify literary and artistic mediums through which testimonials have been offered. The study suggests that each testimonial and the experience it relates forms a trinitarian spirituality, indeed a discipleship spirituality, rooted in Jesus' experience of God. The study will be of personal interest while contributing to research in areas such as spirituality, theology, religious studies, philosophical theology, and philosophy of religion.