Father Hugh Thwaites discusses the teachings of the Church in regard to the discernment of spirits. Excellent guidance for souls desiring insight on discerning God's Will, and help in perceiving more readily which influences derive from grace, and which may come from the enemies of our souls. Father Thwaites addresses at length the teachings left to us by two great saints on this topic: St. Ignatius of Loyola and St. John of the Cross.