Warren's book has been the single most useful compendium of information about the ritual aspects of the Celtic Church, which are of both historical and theological interest, since it was first published in 1881. It includes both a critical account of Celtic liturgy, and a collection of editions of Celtic liturgical texts, Cornish, Welsh, Scottish, and Irish, not all of which has been superseded. This new issue builds on the book's time-tested value by including an extensive new Introduction and Bibliography, which summarise current thought in liturgiology and Celtic history, and which are written with the needs of both Celticists and liturgists in mind. The new Introduction is organised topically, beginning with summary accounts of the developments of liturgy and Celtic history from approximately the fourth century to the eleventh, and continuing with more detailed examination of the specific areas in which the most new work and radical rethinking has been done since Warren's time.It includes references to the most recent or best editions of relevant texts, and to the relevant bibliographies, dictionaries and catalogues, which serve to up-date Warren's own reference-system, and, where appropriate, his editions of Celtic liturgical texts.JANE STEVENSON, of the Department of Anglo-Saxon, Norse and Celtic, University of Cambridge, is a research fellow at Pembroke College, Cambridge.