Synopsis In this book Matilal brings together two decades of thought about the origins, development and nature of Indian logical theory. He traces the evolution of the crucial concept of an inference-warranting relation’ (vyapti) in the early debating manuals and their contexts of informal logic of argumentation. The important contributions of the Buddhist logicians Dinnaga and Dharmakirti are given the weight they deserve, as is the great literature on logic in the late Nyaya School. Throughout this book, Matilal brings to bear his distinctive and sophisticated treatment of the philosophical issues in the theories of the classical Indian writers, by analyzing them in terms of concepts drawn from contemporary philosophical theory. This book will be valuable to students and scholars of Indian thought, and will be useful for philosophers and others seeking a grounding in Indian logic.