This book is intended to contribute to the clarification of the linguistic research area covered by the terms modal, evidential and epistemic. It sets out to demonstrate that on cross-linguistic grounds a hitherto overlooked epistemic meaning domain must be given due recognition in linguistic theory, on a par with domains such as time and number. The relevant domain is coherent, but at the same time complex in that it consists of two subdomains: one which comprises degree-of-certainty meanings, and one which comprises information-source meanings. The book offers three arguments for giving recognition to such a meaning domain. The first argument concerns the clustering of linguistic expressions