Probably the most sensational event in the Catholic Church since the convocation of Vatican II was the announcement by Charles Davis, one of the Church's most distinguished theologians, at the end of 1966, that he was leaving the Church and the priesthood and that he intended to marry. The purpose of this eagerly awaited book is to enable Davis to explain his reasons for the ""break"" and, in so doing, to allow him to appraise his present position as a Christian. As may be expected, A Question of Conscience is an intensely personal book, exploring as it does the gradual alienation, intellectually and emotionally, of a remarkable man from an institution to which he originally had given total adherence at both levels. The core of the book, of course, is the development and definitive formulation of Davis' conclusions concerning the biblical and historical claims of the Roman Catholic Church, and it is these chapters that will interest the theologians and the historians. But what will strike the uncommitted reader will be the utter honesty and consummate courage involved, first, in Davis' decision to leave the Church, and, finally, in recording his transition from Catholicism to Christianity. Given Davis' reputation, his ""press,"" and the quality of his work, A Question of Conscience may well prove to be one of the most important religious books of this decade.