National taxation records are of particular value to historians, providing rare snapshots of both the extent and distribution of wealth and population across an entire country. The Hearth Tax of the 1660s and 1670s provides one such detailed picture of the socio-economic and demographic structure of England and Wales. The Hearth Tax team aims to publish the fullest surviving return for each county (where one has not already been published), together with a scholarly introduction analysing the economic structure, social profile and population density of each county. In addition, the information on hearths sheds invaluable light on vernacular architecture and on developments in building during the later seventeenth century. Four volumes have already been published. The number of volumes currently in preparation is sixteen.