The 'Life of St Germanus', by Constantius of Lyon, is a contemporary account of a fifth-century bishop of Auxerre, who on two occasions came to Britain. In view of the scarcity of texts which give reliable evidence on the state of British affairs at this period, it is remarkable that historians have paid so little attention to this source. Professor E.A. Thompson, one of the leading exponents of the history of late Roman andsub-Roman Europe, has now produced the first book-length study of Constantius' work, bringing to his analysis of it forty years' experience of criticism, of late Latin historical texts, and an extensive knowledge of Continental history as a comparative base. He tries to extract as much information as possible from the 'life' about the religious situation in Britain at the time of Germanus' visits, and the government, the circumstances of the famous Hallelujah Victory', the revolt of Armorica, and so on. He attempts to settle the vexed question of the date of Germanus' death, and he studies the qualities of Constantius himself. The book ends with a description of what may have happened in eastern Britain in the years following Germanus's second visit, a description which challenges many currently held assumptions. This book offers much original food for thought for the student of the late Roman and early mediaevel world. Its arguments, presented in a lively and forceful style, will be not merely required, but very enjoyable, reading.