Charles Sanders Peirce is one of the most original voices in American philosophy. His scientific career and his goal of proving scientific logic provide rich material for philosophical development. Peirce was also a life-long Christian and member of the Episcopal Church. Roger Ward traces the impact of Peirce’s religion and Christianity on the development of Peirce’s philosophy. Peirce’s religious framework is a key to his development of pragmatism and normative science in terms of knowledge and moral transformation. Peirce’s argument for the reality of God is a culmination of both his religious devotion and his life-long philosophical development.