In The Practice of Catholic Theology: A Modest Proposal, Paul J. Griffiths has written a how-to book for Catholic theologians that will both instruct beginners and challenge long-time practitioners to sharpen their understanding of their craft. He defines Catholic theology as the practice of thinking, speaking, and writing about the God of Christian confession; so understood, it's something that anyone can learn to do. Personal sanctity is not required, but as with any other practice, practitioners of this beautiful and elevated thought-performance need to know some things and to develop some skills in order to be able to perform it.