Nicholas Rescher´s ability to discuss difficult philosophical issues in a clear and elegant fashion is well known. These three books resonate with the breadth and depth of understanding and the engaging prose he brings to all of his work. Together, these books present an integrated and unified approach to the key issues of epistemology. However, each stands as a self-sufficient work; allowing readers to approach these books in whatever order best suits their interests. Epistemic Logic examines the nature of knowledge, the conceptual ramifications of the idea, and the reach and limits of what we know.Cognitive Harmony considers why it is crucial to develop our knowledge in a systematic way, and how this facet of knowledge is a key factor for its acquisition and formation. Realism and Pragmatic Epistemology explores the ways we use knowledge, and how it is the successful application of knowledge that at once substantiates and objectifies the things we believe we know.Epistemic logic is the branch of philosophical thought that seeks to formalize the discourse about knowledge. Its object is to articulate and clarify the general principles of reasoning about claims to and attributions of knowledge. This comprehensive survey of the topic offers the first systematic account of the subject as it has developed in the journal literature over recent decades. Rescher gives an overview of the discipline by setting out the general principles for reasoning about such matters as propositional knowledge and interrogative knowledge. Aimed at graduate students and specialists, Epistemic Logic elucidates both Rescher´s pragmatic view of knowledge and the field in general.