This history of the Irish between the fourth and the ninth centuries, from the beginning of the historical period up to the Vikings, flollows only one of many possible approaches to the period. It is, in the first place, a history of the Irish people, and not just of the inhabitants of Ireland. What the Irish did in Britain, Francia and Italy is as much its concern as what they did at home. Secondly, although it gives a major place to the Church, it is a history of a people rather than of books or artefacts. Some surviving texts cannot be given a clear historical context; they are anonymous, only vaguely dated and not attached to any particular institution. Some of them may be of great intellectual importance, but I have deliberately preferred to concentrate on those for which I could propose an historical context. For that reason, the main illustration of Irish artistic production occurs within a chapter on Columba and Iona, while the main discussion of intellectual debate is in the chapter on the paschal question.

Another principle limiting the range of topics covered was that there should be themes connecting one chapter with another. The effect has been to divide the book into three parts, beginning with an introductory section in which the Ireland of c. 700 is presented, first in a discursive manner, through the journey made by Bishop Tírechán's Patrick, and, secondly, more analytically, in the two chapters on Irish society.