This article provides an introduction for the collection of methodologically oriented papers comprising this Special Issue. We define the concept of epistemicity as used in descriptive linguistics and discuss notions related to it – some well-established, some more recent – such as evidentiality, egophoricity, epistemic authority and engagement. We give a preliminary overview of the different types of epistemic marking attested in the languages of the world and discuss the recent developments in the field of epistemic research focussing on methodologies for investigating epistemic marking. In the second part of the paper, we focus on the more practical side of epistemic fieldwork; the types of data that can be used in documenting linguistic expressions of epistemicity and best practices for data collection. We discuss the experimental methods that are used in the description of epistemic systems, both those developed for this particular purpose and those adapted from other types of linguistic research. We provide a critical evaluation of those materials and stimuli and discuss their advantages and disadvantages. Finally, we introduce the contributions to the Special Issue, discussing the languages studied by the authors of the contributions and the fieldwork methods they used in their research.