What is biblical theology?  Is it simply theology that is faithful to the Bible?  While biblical theology does aim at being faithful to the Bible, it is not simply this.  Biblical theology is a discipline in the way that systematic theology and historical theology are disciplines.  I would argue that biblical theology is the prince of the theological disciplines, but that it should not be seperated from the discipline of systematic and historical study.  Goldsworthy has a nice article on this at 9marks.  Thanks, JT for the article!