This book provides an account of the Triune God that attempts to offer remedy to the problems of current theological and philosophical interpretations by returning to and developing the intuitions and solutions put forward in the Patristic tradition and Plotinus’ philosophy. It puts forward a solution that clarifies the account of God in terms of pure existence and, through the Christological conception of hypostasis, understood in line with some Patristic insights as the existential principle of being. It presents this solution as a rationally acceptable way of speaking about the unspeakable, espousing the mode of discussion developed by Plotinus in his consideration of the One, which, as the First Principle, is beyond being. The volume makes recourse to Plotinus’ and Patristic conceptualisations when accounting for differences between hypostases that are One Triune God. As a result, it offers an approach that allows for an existential elucidation of the Triune God which is an alternative to the construals currently prevailing within philosophical theology. While the Trinity is usually interpreted in terms of essence and substance, the author conceptualises the Divinity as pure existence, fully identical with each of hypostases-principles-of-existence, while acknowledging that hypostases remain really different from each other via their modes of existence. This book is of interest to those within philosophical theology and analytical theology, scholars of dogmatic theology of various denominations focusing on Trinitology and Christology, and students of Christian theological and philosophical thought.