Keith Lehrer is one of the leading proponents of a coherence theory of knowledge that seeks to explain what it means to know in a characteristically human way. Central to his account are the pivotal role played by a principle of self-trust and his insistence that a sound epistemology must ultimately be ecumenical in nature, combining elements of internalism and externalism. The present book is an extensive, self-contained, up-to-date study of Lehrer's epistemological work. Covering all major aspects, it contains original contributions by some of the most distinguished specialists in the field, outgoing from the latest, significantly revised version of Lehrer's theory. All basic ideas are explained in an introductory chapter. Lehrer's extensive replies in a final chapter give unique access to his current epistemological thinking.