Saint Francis de Sales (1567-1622) was born in France to a wealthy family. Though he initially followed his father's direction and became a lawyer, he was drawn to the priesthood, and became the Bishop of Geneva in 1602. Francis was a spellbinding preacher, and a kind and gentle friend to all. His immensely popular writings clarified Catholic teachings in an era of bitter and confusing rivalry between Catholics and Protestants. His Introduction to the Devout Life and Treatise on the Love of God introduced lay people to spiritual direction and spiritual formation. Francis became a saint in 1665, and a Doctor of the Church in 1877.

John Kirvan, who died in 2012, wrote primarily about classical spirituality. He conceived the 30 Days with a Great Spiritual Teacher series and edited most of its seventeen titles. Kirvan's other books include God Hunger, Silent Hope, Raw Faith, and There Is a God, There Is No God.