Despite being published in 1888, this is a good introductory tome that covers the exile of Dermot MacMurrough (1166), through the Anglo-Norman invasion, particularly under Richard de Clare, and finishes up with the defeat of John de Courcy and the assassination of Hugh de Lacy (1186).

It is written in excerpt form bases upon the writings of the day, notably Gerald of Wales, the Annals of Clonmacnoise, the Annals of the Four Masters, Roger of Hoveden and the Annals of Ulster.

A decent entry level history of the period - a jumping off point for more indepth research.