This thesis is an investigation of the traditional dialect of Gloucestershire. The concept 'traditional dialect' is examined in the Introduction, as is the nature of the county itself. The data for the investigation is the Survey of English Dialects (SED), the nature of which is also discussed in the Introduction. Where this investigation differs from other studies, however, is that its core data is not the published Basic Material of the SED but the notebooks of the original fieldworkers. This allows a detailed consideration of the process of transmission by which the data passed from notebook to published volume. Editorial practices are evaluated, omissions and errors noted, and the value of the original material stressed. This is one of the primary outcomes of the investigation, and fonns the second chapter ofthe thesis. The succeeding chapters, three to ten, analyse the data from the notebooks of the seven localities visited by the SED fieldworkers in Gloucestershire. They consider phonological, grammatical and lexical material with the aim of arriving at a description of the dialect found in those seven localities. Preliminary investigation suggested that these localities share the broad characteristics of the south-west, but that while this is true to a marked degree in the most southerly localities it is much less the case further north. Therefore a further aim of the investigation is to see whether a major isogloss runs through the county, and to consider issues such as boundary and transition. This is the main subject of the concluding chapter, which also compares earlier studies where dialect areas in the south-west have been identified.