These, Bishop Kirk's Bampton Lectures of 1928, have been recognised as amongst the most important and readable works of moral theology published in the twentieth century. They provide a reasoned justification for the centrality of worship in Christian life, within the context of moral theology and ecclesiastical history. Concentrating on the development of ascetical theology in the early church, Kirk asks, "Are rigorism, self-abnegation and world-flight no more than obsolete ideals of other days, or have they too an underlying principle of which the Church and the Christian are still in need?" Despite the massive learning on which it is based, Kirk's study of the Christian doctrine of the 'summum bonum' never loses its way in a labyrinth of detail.