The book comprises six lectures delivered in the Divinity School, Cambridge in the Lent Term of 1964. The main concern of the author is the moral challenge to Christian theological ethics from the secular humanist who has a high sense of moral responsibility without any belief in God or in personal immortality. If these lectures only touch upon the ultimate questions about the nature and status of moral personal being, they will enable some secular humanists and some Christians to enter upon conversations which may prove useful to both. In his first chapter the author considers the contemporary challenge to theological ethics from highly moral secular humanism. In particular, he examines the vocabulary which the secular humanist and the Christian are using in speaking of the moral standard. In the five chapters which follow, he deals largely with the diversity of ethical judgement as applied to particular situations. He avoids the use of technical terms.