The link Yankee gave is excellent, here is a brief overview as well.<br><br>Theology may be studied from several different reference points. Additionally, it may be studied from different views. As there are different methods of investigation in criminal matters (witness interviews, forensic investigation, background investigations, crime scene investigations, legal investigations, etc.) so are there different approaches to studying the doctrine of the Scripture. Each system of theology has its place in the study of doctrine and theology and aid in our understanding of a systematic theology, but they differ in scope, content, and evaluation methods. <br><br>Historical Theology --the study of what Christians in different periods in the past have understood about various theological topics<br><br>Philosophical Theology --studying theology using philosophical interpretations of what can be known about God from examining the universe, largely without the use of Scripture<br><br>Apologetic Theology -- the study of presenting arguments for the truthfulness of the Christianity for the purpose of convincing others and defending Christianity<br><br>Old Testament Theology --studying all the theological topics of Scripture from the Old Testament point of view<br><br>New Testament Theology -- studying all the theological topics of Scripture from the New Testament point of view<br><br>Biblical Theology -- containing a study of both Old Testament Theology and New Testament Theology, as defined above, but giving special attention to the teachings of individual authors and doctrines of Scripture, and placing each of these teachings in the historical development of Scripture.<br><br>It is impossible not to include some of each of these elements (historical, philosophical, and apologetic matters) in any Systematic Theology that is written. This is because history enlightens us of the knowledge gained and the errors made by others in the past in understanding the Word of God. Philosophy assists us to comprehend right and wrong forms of logic in our society, as well as in other cultures. And what use would a systematic theology be if apologetically it did not facilitate us in answering some of the objections of unbelievers and aid in clearing up some misunderstandings in Scripture? <br><br>Though biblical theology is very close to a Systematic Theology there some variations. A Biblical Theology investigates the historical development of a doctrine and the way in which one’s perception at some point in that historical development affects one’s comprehension and application of that particular doctrine. Biblical Theology also focuses on the understanding of each doctrine that the biblical authors and their original hearers or readers possessed, where a Systematic Theology makes use of the material of Biblical Theology and often builds on the results of Biblical Theology (more a statement of the facts of a Biblical Theology and less overall development of the actual theological investigation). <br><br>At some points Systematic Theology will even use a biblical-theological method, analyzing the development of each doctrine through the historical development of Scripture. This is to alleviate any misunderstanding of certain texts of Scriptures. But, the heart of Systematic Theology still remains different: its focus is on the collection and then the summary of the teaching of all the biblical passages on a particular subject.

Reformed and Always Reforming,