Dr Heslinga contributes to a better understanding of the history and geography of Ireland by presenting a study of the political frontier which separates the Republic of Ireland  from the United Kingdom of Great Britain and Northern Ireland. This frontier consists of two parts: the land boundary which crosses the island of Ireland, separating Northern Ireland from the Irish Republic, and the sea boundary between the Republic and Great Britain. He examines in how far these boundaries conform to major regional divisions of the British Isles, at present as well as in the past. He shows that both the sea and the land boundaries originate in a desire to preserve and, in the case of the Republic, ti accentuate regional contrasts. As he see it, these contrasts - like those between England and Wales and between England and Scotland - are basically cultural, in as far as they reflect linguistic and religious differences. One of the somewhat provoking suggestions made by the author is that one should look at the British Isles not only in the conventional way as containing a large eastern and a smaller western island, but also as consisting of a large southern and a smaller northern part. In his opinion the Irish land boundary could be interpreted as a cross-Channel extension of the Scottish Border, marking off, in a very arbitrary way, the 'scoticized' part of Ireland from the most anglicized part.