Carson on Biblical Theology

I have heard the term thrown around a lot and often have been left scratching my head. This explanation clarifys why:

"Biblical theology" has become a highly disputed expression. Some use it to refer to the theology of individual biblical books or corpora (e.g., the theology of Matthew, the theology of Paul). Others use it to refer to the theology of the Bible when the Bible is studied diachronically, over against systematic theology, which tends to be organized topically, synchronically. As subsets of this latter category, there are two further refinements. When some hear the expression "biblical thology," they think of how various themes can be traced right through the Bible, or through large parts of it...Others reflect on what I have called "the great turning points in redemptive history.

~D. A. Carson's Christ and Culture Revisited