Reports on an excavation programme developed by the Dyfed Archaeological Trust following its formation in 1975. The concentration of enclosures in the south-west of Wales was a well-known phenomenon, but their origins and development were poorly understood. The excavations showed activity from the Early Bronze Age to the post-Roman period. The volume presents seven sites in detail and considers the nature, function and status of the enclosures as well as the sequence and economy of the sites as a whole. With contributions by D. Benson, E. Besly, D. Brennan, A.E. Caseldine, P. Crew, J. Crowther, T.C. Darvill, A. David, T.G. Holden, B. Levitan, C. O'Mahoney, J. Webster and J.L. Wilkinson. Edited by Kevin Blockley.