This scholarly work is an attempt to explain two issues: first, the exceptional longevity of the Waldensian sect which was the only medieval sect to survive until the Reformation when it merged with the Calvinist Church; and, second, why the sect came to an end when its members renounced some of their beliefs, their organisation, customs and traditional way of life. The author's convincing view is that it was the barbes – the itinerant ‘preachers by night’, the backbone of the sect's organisation – who kept it alive, and also that it was their decision to unite with the Calvinists. He shows that after that step the Waldensians no longer needed to live clandestinely, disguising who they were, but that as a result they lost their distinctiveness and religious originality. The first chapters of the book deal with the period from the emergence of the sect in the 1180s to the fourteenth century. However, the detailed and important contribution of the study relates to the period from the fifteenth century until the Synod of Prali (1533). The author also discusses the problem of historical sources, mostly Catholic and hostile. As it was in the west of the Waldensian diaspora that the barbes emerged, and as more is known about them than about their eastern counterparts, the study concentrates upon them. The author discusses the way they were recruited, their social origin, their training and way of life, their investiture as well as the self-imposed secrecy, which was essential for the survival of the sect. He demonstrates the deep esteem and admiration that the Believers felt for them, and the way they internalised the theological and moral tenets developed in their sermons. I beg to differ only with his conclusion, based on some testimonies before the courts of the inquisition, that the sexual behaviour of those devoted and admired barbes was far from being without blemish. He offers no convincing evidence for this view. A touching reminiscence of the Waldensian past is the choir of Torre Feliche. In a radio interview in 1982 Primo Levi asked to listen to one of their songs. He added that he used to sing that song and others of the rich Waldensian repertoire to his baby daughter who was born in 1948.