In the Catholic Tradition our spiritual writers are usually religious professionals of one kind or another - Contemplative nuns and priests or theologians. This is not the case with Charles Whitehead, who is married with four children and was a marketing executive in the paper industry all his working life.
Had he not had a special encounter with God in his 30's and been baptised in the Holy spirit, his writing gifts would no doubt have been confined to business reports and technical articles.