In Jay Rosenberg's lively and accessible introductory dialogue, four bright students explore a number of the central topics and problems of contemporary epistemology -- scepticism and certainty, internalism and externalism, foundationalism and coherentism, and the nature and limits of justification. Their wide-ranging discussion highlights many of the vivid and imaginative thought-experiments that have shaped both classical and contemporary reflections on the scope and character of our knowledge of the world.