Joan Carroll Cruz was a native of New Orleans and was the educational product of the School Sisters of Notre Dame. She attended grade school, high school and college under their tutelage. Mrs. Cruz was a tertiary in the Discalced Carmelite Secular Order (Third Order) since 1968; for eight years she served as Mistress of Formation (Novice Mistress).
For her non-fiction books, Joan Carroll Cruz depended heavily on information received from foreign shrines, churches, convents and monasteries. Her books include The Incorruptibles, published in 1977; Desires of Thy Heart, a strongly Catholic-themed novel, also in 1977; Relics, published in 1983; Eucharistic Miracles in 1987; Secular Saints in 1989; Prayers and Heavenly Promises in 1990; Miraculous Images of Our Lady in 1993; Miraculous Images of Our Lord in 1995; Mysteries, Marvels, Miracles: In the Lives of the Saints in 1997; Angels & Devils in 1999; and Saints for the Sick in 2010.