As its title indicates, this thesis is concerned with the echtrae as a genre m early Irish literature Chapter I looks at the basic use of the term in medieval Irish tale-lists and elsewhere, and then briefly considers modem scholarship and vanous issues raised by it regarding the nature and function o f the pre-Norman Irish echtrae Chapter H endeavours to gather such information as is available about echtrae titles attested in the tale-lists and then to examine the medieval provenance (or lack of it) of the use of the echtrae to refer to various tales often associated with the genre Narratives for which this can be established form the initial database of seven tales examined in Chapter III, which proposes a preliminary taxonomy o f what can be regarded as reasonably typical echtrai in the light of ten significant common elements Chapter IV augments this rather restricted corpus with five further texts selected for similar analysis on the strength of significant typological affinities with the group considered in Chapter III The role of sovereignty or kingship, which emerges as a central concern o f echtrai in Chapters III and IV, will be examined further in Chapter V, which will also look at the royal or other connections o f the persons named in the titles o f various lost echtrai Chapter VI explores the way in which sovereignty and other motifs are exploited in individual extant echtrai Chapter VII examines stones relating the otherworldly expeditions o f Cu Chulainn and their relationship to the echtrai Finally, Chapter VIII endeavours to summarise the main findings and attempts to sketch the development o f the echtrae in the pre-Norman period.