The subject has been treated by many writers; yet there seems to be room left for a popular exposition which addresses itself to the general public and deals with the most recent phases of the question and the position created by the definition of the Vatican Council. Professor Hettinger insists much on three fundamental ideas of Christ's kingdom, viz.: the idea of a Church, the idea of the unity of the Church, and the idea of Church government. Holy Scripture describes. the Church in magnificent language. She is 'the city of our God, ' 'the city of the great King, ' 'the city of the Lord of...