Although sometimes presented as a branch of the philosophy of religion, philosophical theology is more often seen as a branch of theology, and includes but is not limited to natural theology (the branch of theology that attempts to use reason in order to demonstrate the truth of religious claims).
- J. Deotis Roberts A Philosophical Introduction to Theology. London: SCM Press, 1991. ISBN 0 334 02494 3
- Kames F. Ross Philosophical Theology. Indianapolis: Bobbs-Merrill Co., 1969.