The ancient monuments of Wales and Monmouthshire placed in the guardianship of the Office of Works (and its successors) were interpreted through the preparation of some 50 guidebooks and leaflets from the 1920s to the formation of the Department of the Environment in 1970. The initiative lay with the Chief Inspector, (Sir) Charles Reed Peers, who prepared the guide for Caernarfon Castle. One of the most prolific authors was C. A. Ralegh Radford, one of the Inspectors, who wrote some 21 guides for sites in Wales. Although the guides for Wales covered the major castles and ecclesiastical structures, from the 1930s interpretative guides were written for a number of prehistoric and Roman sites, including the amphitheatre at Caerleon by (Sir) Mortimer Wheeler. The souvenir guides introduced in the 1960s laid the foundations for the new series of Cadw site booklets that include reconstructions and plans.
David WJ Gill (Thu,) studied this question.