The inventor of pragmatism, Charles Peirce is a seminal figure in the development of modern logic. His searching investigations in the "logic of science" have profoundly influenced subsequent work in epistemology and the philosophy of science, and his semiotics has had a similar impact on the philosophy of language. By contrast, Peirce's philosophy of mathematics has received relatively little attention, despite its centrality to his thought and the depth of his insights into the perennial problems of the subject. This book changes that. Here, philosophers look afresh at this neglected but vital dimension of Peirce's thought. The essays are wide-ranging in their coverage, with in-depth discussions of a range of topics.