the National Library at Aberystwyth.2 In addition, a printed transcript of the church book, together with a most useful introduction has recently been produced.3 Copies of this transcript have kindly been placed by the authors in a number of repositories, including the West Glamorgan Record Office, thus avoiding the need for the often pleasant but always time- consuming journey to Aberystwyth. The purpose of this article is to draw attention to this resource as well as to examine the contents. The church book itself is a leather bound volume measuring about twenty centimetres by seven centimetres. It dates from 1700, when the worst excesses of religious persecution had been ended, for most Pro- testant dissenters at least, by the Toleration Act of 1689. The material which the book contains extends from the late seventeenth century to the close of the eighteenth century, thus covering a period of about a hundred years. It is written almost entirely in English, even though the congregation worshipped in the Welsh language. Lewis Davies, who served as minister from 1693 until 1710 was responsible for recording most of the earlier items, whilst Lewis Rees, whose pastorate was from 1759 until 1800 was responsible for the remainder, although there are occasional contributions by other writers. In addition, it appears that there was an even earlier collection of materials ("the large church book") but sadly this has not survived. Fortunately however, some of the items in this missing book appear to have been preserved in the existing work. Like any historical source, there are weaknesses which must not be overlooked. In chronological terms, the coverage is far from complete. There is a mass of material for the period from 1688 to 1710, after which there is nothing until 1731-2 when there is one item only. The records then recommence in 1759 and cover almost the remainder of the century. The last item of any significance belongs to 1792; a collection of financial accounts dated 1800-1 can be disregarded. In addition, the church book appears to have had a somewhat chequered history. Some items appear to be missing, whilst others are copies of originals which have apparently been removed at some time in the past. Moreover, the contents are set out in a disorganised way, possibly because the book may have been taken apart and rebound on more than one occasion. In the transcript the materials have been re-arranged in a more orderly manner to facilitate ease of use. Despite these shortcomings however, the church book provide us with an unique source of information about one of the most significan dissenting causes in the locality. The cause which eventually became known as the Mynyddbach Churcl had already been in existence for a considerable number of years befor the existing church book was begun. A short memorandum in the boo] contains the following statement which is the earliest definite evidenc about its early history: