Theology, according to J.I.Packer, consists of ten linked disciplines.  They are:-

1. Exegesis – which asks, “what was this biblical text written to convey to its readers?”
2. Biblical theology – which asks, “what is the total message of the canonical books on this or that subject?”
3. Historical theology – which explores how Christians in the past viewed specific biblical truths.
4. Systematic theology – which rethinks biblical theology with the help of historical theology in order to restate the faith, topic by topic and as a whole, in relation to current interests, assumptions, questions, hopes, fears and uncertainties in todays church and world.
5. Apologetics – which seeks to commend and defend the faith as rational and true in the face of current unbelief, misbelief and puzzlement.
6. Ethics – which systematises the standards of Christian life and conduct and applies them to particular cases.
7. Spiritual theology, sometimes called devotional or ascetic theology or Christian spirituality – which studies how to understand and maintain sanctifying communion with God.
8. Missiology – which aims to see how God’s people should view and tackel their gospel-spreading, church-planting and welfare-bringing tasks across cultural barriers and world-wide.
9. Liturgy – which asks how God is best and most truly worshipped, and how true worship may be achieved in existing church.
10. Practical theology, embracing pastoral theology, family theology and political theology as it explores how to further God’s work and glory in home, church and socieyt.

J.I. Packer, ‘The Preacher as Theologian’, in When God’s voice is heard, 80.