The guidebook presents the collection of a Roman milestone, early Christian inscriptions, and later monastic material that were moved into the old School House at Margam in 1932.
The guidebook by C.A. Ralegh Radford starts with a history of the area that allows the material in the museum to be placed in context: The Silures and Glamorgan in the Roman period; the restoration of native rile and the introduction of Christianity; the early Christian memorial stones; the formation of Glamorgan; the Celtic monastery at Margam; the pre-Romanesque crosses; the later history of the kingdom of Morgannwg; the Norman conquest of Glamorgan; the Cistercian abbey of Margam.
The second half includes a description of the pieces, starting with the early 4th century Roman milestone from Port Talbot (RIB 2254).
The guidebook includes a plan of the museum showing how the stone were displayed.