Since the time of the Enlightenment, efforts have continued to engage science and theology. In Participating in God, Powell has endeavoured to understand the world intellectually in a manner that is both faithfully Christian and scientifically responsible. He comes to his task with two basic assumptions: (1) the Christian faith is true, and (2) the world image as it is known by the natural sciences is reliable. He presents a systematic theology of the doctrine of creation and the doctrine of the Trinity as they intersect with the current understanding of the universe. The doctrine of creation has been understood based upon the current philosophical and scientific understanding of each historical period.

Powell sees the need to understand the doctrine of creation as it intersects with our twenty-first-century world-view. Since he sets forth his understanding of how creatures participate in the trinitarian life of God, he finds that this concept ties the doctrines of creation, the Trinity and the new creation together in a manner that preserves the systematic character of theology. He approaches his task by situating the doctrines of the Trinity and creation in their historic Christian setting. In developing his understanding of the universe in a trinitarian fashion, he utilises a paradigm that encompasses an understanding of the physical universe, the biological world, human existence, the conditions of finitude and the kingdom of God. He weaves all of these into his systematic theological approach and from the output of this study develops an understanding of the trinitarian ethical dimension of the doctrine of creation. The primary contribution of this book is to establish a close linkage between the current scientific understanding of the universe and its intersection with the doctrines of creation and the Trinity as they together create a human ethical response for the twenty-first century.

In Part One: Creation and Trinity, Powell summarises the historical development of the doctrine of creation He establishes certain basic premises: (1) the creator is the triune God attested to in the Bible; (2) this triune creator alone is the basis of creation; (3) the triune creator is distinct from the world that has been created; and (4) the triune creator's relationship to the created world is compatible with this last distinction. Thus there is a regulative dimension that is historically dynamic, with a participation by created beings in the trinitarian life of God. This participation by creatures is based on a life that embraces identity and difference. Just is the triune God is based on the identity of the three persons as one, so it is also based on the differences that are present in each person of the Trinity, just as individuals participate in the life of God based on their own modes of being. However, the kingdom of God has appeared in the midst of human finitude and sin. Although the kingdom does not overcome the effects of finitude since creatures remain creatures and do not become divine, it does overcome the distortions of finitude under the condition of sin.

In Part Two: Understanding the Universe in a Trinitarian Way, Powell masterfully interweaves a clear and concise understanding of the natural world in both its physical and biological aspects with his understanding of the doctrines of creation and the Trinity. He states that, in the kingdom of God, through receiving a new past and a new future we receive our identity. Thus death is not the decisive event that gives meaning to our lives. Owing to the generic and individual features that mark the universe both physically and biologically, there is a similar aspect to the human condition of finitude. This plays itself out in our understanding of the kingdom of God, which is symbolic of the ideal community. A key component to understanding the kingdom of God is recognising that it is God's response to the distortion that sin produces in the world. Thus nothing in the universe can be considered as ultimately real except through its interconnectedness to all the other realities. This, according to Powell, is the meaning of the finitude of creatures.

In Part Three: A Trinitarian Ethics, Powell considers the ethical dimension of the doctrine of creation both from an historical point-of-view and with a consideration for its meaning today. Throughout Christian history, world transcendence has taken various forms which have been highly dependent on the cultural situation in which the church conceived ‘the world’. Powell finds that our encounter with the creator leads us as humans to consider our finitude and therefore our place in the world God has created. Powell states that we are always faced with the temptation to interpret the doctrine of creation as a theory about our natural world and its origins. Thus the doctrine is not a theory but a definite way of being in the world; i.e. a practice of life in the world. Powell brings the book to a close with a practical call to live out the doctrine of creation by recognising that an ethical transcendence of the world is a call to surrender the consumer culture that is a modern form of narcissism, which reduces humans to consumer status and everything else to a commodity.

Powell has provided a highly useful and thoughtful approach to the doctrine of creation by grounding it in the doctrine of the Trinity. All too often in the twenty-first century, concern for the doctrine of creation revolves around issues of contrasting scientific and biblical accounts of the act of creation itself. Powell has provided a significant corrective to this misappropriation of the intersection of science and theology. He has chosen instead to direct his attention to the coalescence of twenty-first-century natural science as it interacts with the doctrine of creation. As he develops his argument, he clearly demonstrates that there is no incompatibility between the two. Their coalescence results in a clear expression of the understanding that when the doctrine of creation is looked at through the lens of science, and vice versa, the Christian is enabled to use the doctrine of creation as an approach to understanding the immensity of the goodness of what God has created and thereby understand its impact on the ethical decisions each Christian makes in the twenty-first century.