This study takes as its subject matter the use of social space in early medieval Irish houses (c. AD 600-1200), with the evidence from the province of Ulster interrogated in more detail. During this period there is a shift from curvilinear to rectilinear house forms. Excavation reports, published and unpublished, have been widely consulted and are the main focus for this research. The Old Irish legal tract Crith Gablach, composed during the earlier part of the early medieval period, is analysed in particular detail with reference to its information about houses and social status. The earlier chapters include a review of earlier research in Ireland and elsewhere including a range of archaeological and anthropological house-related research.