Despite never having been previously published, Ann Hamlin's pioneering study on the archaeology, architecture and history of the early church in Northern Ireland, her Phd thesis, has proved influential, not least for the wealth of information it presents, and the skill with which it synthesises information from different disciplines. The work forms a gazetteer of 266 sites related to early Christianity, many identified for the first time, together with a discussion section. This considers numbers, distribution and topography of sites and the different classes of material evidence (enclosures, churches and other buildings, burials, carved stones, ballauns, wells, ecclesiastical metalwork and evidence of economy and technology). It also integrates written and place-name evidence.