Following his account of Irish origins as evidenced by archaeology, genetics and linguistics, J. P. Mallory returns to the subject to interrogate what he calls the `Irish Dreamtime': the native Irish retelling of their own origins, as related by medieval manuscripts.

He attempts to explore the reality of this version of the earliest history of Ireland, which places apparently `mythological' events on a concrete timeline of invasions, colonizations and royal reigns that extends even further back in time than the history of Classical Greece. Can the accounts of this `Dreamtime' really inform us of the way of life in Iron Age Ireland? By comparing the world depicted in the earliest Irish literary tradition with the archaeological evidence available on the ground, Mallory explores Ireland's rich mythological tradition and tests its claims to represent reality.