Throughout his work, Paul Tillich critiqued the traditional monotheistic idea of God as a being alongside the world with definable properties, and he sought to replace this idea of God and the God-world relationship with another one. He regarded this replacement as vital for establishing a believable Christian theology, a relevant philosophy of religion, and a mutually beneficial understanding of the relationship between religion and contemporary culture. In this work of philosophy of religion geared to the non-expert, Olson explains Tillich’s idea of God and the God-world relationship, showing how, for Tillich, God is both infused throughout the world and transcendent of it. Olson analyzes the implications of Tillich’s idea of God, contrasting it with the positions of deism, conventional theism, and pantheism, while also arguing for the continuing relevance in the contemporary period of Tillich’s idea vis-a-vis these other approaches. Olson unfolds the epistemological approach of Tillich’s understanding of God, whereby God is immediately present to all reflection and action. He shows the way in which Tillich’s idea of God brings forth illuminative categories for the philosophy of religion, including the meaning of symbolic language for God and the distinctive dynamics of religious expression. Finally, Olson shows how Tillich’s idea of God opens the door for a non-reductive, mutually enhancing understanding of the relationship between religion and culture, and he unfolds the dynamics of that relationship.