This pioneering study of Christian sun symbolism describes how biblical light motifs were taken up with energy in the early Church. Kevin Duffy argues that, living in a world of 24/7 illumination, we need to reconnect with the sun and its light to appreciate the meaning of light in the Bible and Christian tradition. With such a retrieval we can appreciate Pope Francis's insistence that, like the moon, the Church does not shine with its own light, and assess the claim that the Eucharist is to be celebrated 'Ad Orientem', that is towards the rising sun in the East. Liturgy, architecture, poetry and the writings of saints and theologians such as Augustine, Hildegard of Bingen, Francis of Assisi, and Thomas Traherne offer abundant resources for a much needed ressourcement. While Christ was preached as the True Sun among sun-worshipping Aztecs, and the consecrated host was placed in a solar monstrance on Baroque altars, in the modern era solar themes have been neglected. In this accessible work, the author suggests that we rebalance a spiritual symbolism that has over-emphasised darkness and cloud at the expense of light and sun. He proposes a creative retrieval of the traditional title of Christ as the Sun of Justice. This title blends the personal, the social and the cosmic/ecological, and speaks powerfully to a secularising era that contemporaries Friedrich Nietzsche and Therese of Lisieux both described as one where the sun does not shine.