Modality is a linguistic notion linked to the meanings of "can," "must" and other auxiliary verbs. It is a very popular research topic nowadays, yet many linguists are not too comfortable trying to define it. This book shows that modality as traditionally understood is not coherent because it was designed to fit the characteristics of European languages. The book argues that basic modal categories, rather than modality itself, should be placed at the center of linguistic research. For instance, epistemic modality concerns the linguistic expression of certainty and uncertainty, constituting a basic tool in our interaction with the world that should not be included under a wider conceptual category. These theoretical ideas are applied to the description of Galician, an understudied Romance language.