This book brings together for the first time all 260 surviving documents issued by, or in the name of, all the Scottish bishops of the twelfth century, when written acta first appear in Scotland. Every Latin text is printed in full, preceded by an English summary and followed by an explanation of the date ascribed to each document and, where appropriate, textual notes and comments. Originals are described in detail: endorsement, physical condition and seal. The sources are archives in Scotland and England, the Archives Nationales, the muniments of four private owners and the copies made by antiquaries in the eighteenth and nineteenth centuries. The introduction provides the first account of the diplomatic of the bishops' acta, and (other than individual biographies) of the role of the episcopate in twelfth-century Scotland. Overall, the volume is a mine of information on the activities of bishops, the personnel of episcopal households, landholding, economic activity, early burghs, the parochial system, the settlement of disputes, and the bishops' relations with other great men of the realm, the papacy and religious houses, and the bishops as founders and builders. Norman F. Shead is an Honorary Research Fellow at the University of Glasgow,