The majority of Christian and religious writing could most likely be put under the category of philosophy and theology. A book under this topic could take forms of various kinds. One could write a biblical or systematic theology; a specific theological topic could be tackled; a cultural or philosophical issue could be addressed; topics of this nature have also been tackled through biographies, like that of Augustine's Confessions. Writing under this category would serve as edification for the church, or it could potentially change the mind of an unbeliever by being utilized as a tool or instrument for the Holy Spirit. This is yet another way to grow the kingdom of God.