This work, first published in 1944, provides the most reliable texts of the Lives of Welsh saints based upon the Cotton MS in the British Library from 1200. Out of print for over 50 years this work is still the standard edition of these Lives and is still widely used by scholars today. As well as being the major text for our information concerning the Welsh saints it also contain some of the earliest Arthurian material and are the first to make Arthur a king. The Editors have taken this opportunity to add some additional material in the way of: a new introduction reviewing the scholarship on the subject of Welsh saints over the last 60 years, written by Tristan Gray-Hulse; two new sections by Thomas Jones and J Conway Davies which contain additional information on the texts; a translation and detailed commentary on the Life of St Beuno (Buchedd Beuno) by A W Wade-Evans, not included in the original edition. The lives of 11 saints are included in their original language with a facing page English translation and six genealogical tracts that provide even more biographical information from medieval Welsh tradition.