The Celts as the classical world met them and as archaeology finds them, then the mythology itself: the Tuatha Dé Danann and the invasions, Cuchulain and the Táin, the Fenian cycle and Oisín in the Land of Youth, the voyages, and the Welsh Mabinogion — with the historical framework that makes sense of them.
The standard one-volume Celtic mythology, beautifully told. Download the free EPUB.