His spiritual biography on how certain Catholic saints & holy people came to influence his life. Examples: Saint Therese of Lisieux, Thomas Merton, Ignatius Loyola, Dorothy Day, etc.
His idea makes for a nice writing exercise for those inspiring writers out there. Who are your inspirations in faith, and why are they? How are they influencing you? What lessons do you draw from their lives? The person can be from any time & place and not necessarily well-known.