The Encyclopaedia of Celtic Wisdom is, hands down, required reading for anyone interested in the primal Celtic traditions, especially of the Irish and Scottish traditions. Where John Matthews' Taliesin and the Shamanic Mysteries of Britian addresses largely a Cymric (Welsh) and British leaning, The Encyclopaedia of Celtic Wisdom is, largely, rooted in the Irish, with some exploration of folk Scots beliefs and expressions of the shamanic (as in the case of the late and well-loved Scottish seer, Eliadh Watt). As of January 2002 I consider this book to be one of the top three books on Celtic tradition, especially the visionary tradition of primal Celtic spirituality and the field of contemporary Celtic spirituality. It is a priceless addition to one's library, along with Tom Cowan's Fire in the Head: Shamanism and the Celtic Spirit, Mara Freeman's Kindling the Celtic Spirit. For a more classical exploration of these same themes I recommend The Silver Bough, by F. Marian McNeill.