Witta: An Irish Pagan Tradition (Llewellyn's World Religion & Magick)
Rather than focusing purely on Celtic mythology, Witta  examines the cultural aspects of Irish paganism and serves as a  textbook for the practice of the old religion of Ireland. It's clearly  written, well detailed and researched with a fair bibliography plus  history, spells, rituals, sabbats and more. The author supplies a list  of resources for hard to find herbs, ritual tools and other important  implements.