In its broadest terms, historical dialectology might be defined as the study of diachronic, diatopic and social variation in the historical record of languages. Insofar as it is historical it deals with time: the varieties spoken at particular points in history and the transitions between these points. Insofar as it is a study of dialects, it deals with variation across geographical and social space, broadly understood. The granularity with which we may observe the variants themselves, as well as their distribution across these key dimensions, is constrained by the quality, quantity and dispersion of the data itself, as well as our knowledge of the extralinguistic context they belong to. Given this remit, historical dialectology is intrinsically multidisciplinary. While at its core it sits at the crossroads of historical linguistics and dialectology, the questions it addresses are informed by sociolinguistics, history, palaeography, stylistics, critical theory, statistics, theoretical linguistics, corpus linguistics and a number of other (sub)disciplines. This volume brings together these manifold aspects of the discipline taking the ideas first developed by Angus McIntosh in the Middle English Dialect project and applying them - via powerful new digital tools - to varieties of English and Scots. The authors' focus is on a small set of closely related linguistic varieties spoken in the Medieval and Early Modern periods, nevertheless, they sketch out a number of key methods which may be fruitfully employed in probing the historical dialectology of other linguistic families and time periods.