It would be hard to exaggerate the importance of a book like this to those who use the Episcopal Book of Common Prayer regularly for worship and teaching. The Rev. Wm. Sydnor, rector of Christ Church, Alexandria, Virginia, supplies a most useful commentary on the Lessons, Psalms, and other Biblical passages appointed for use on the Sundays and Holy Days of the Christian year, setting forth the themes to be found in these selections and showing their relationship to the Church Year. Laymen will find this companion to the Prayer Book almost essential to its fullest use and understanding and the clergy may well be grateful for such a book for their own use, for the expositions are truly simple and therefore of greatest use in teaching and preaching.