Coire Sois, The Cauldron of Knowledge: A Companion to Early Irish Saga offers thirty-one previously published essays by Tomas O Cathasaigh, which together constitute a magisterial survey of early Irish narrative literature in the vernacular.

O Cathasaigh has been called "the father of early Irish literary criticism," with writings among the most influential in the field. He pioneered the analysis of the classic early Irish tales as literary texts, a breakthrough at a time when they were valued mainly as repositories of grammatical forms, historical data, and mythological debris....

The Mabinogi, a classic of Welsh literature, is a suite of four stories in Middle Welsh. They were composed, or at least put into their current form in the late eleventh or early twelfth century. Set in a primal past, the Mabinogi bridges many genres; it is part pre-Christian myth, part fairytale, part guide to how nobles should act, and part dramatization of political and social issues.