Theology proper is the study of God. God the Father, God the Son, and God the Holy Spirit. The triunity of God. However, a systematic theology is not just a study of God but also everything He says in His Word concerning creation, man, angels, sin, life, death, salvation, law, faith, Israel, His church, judgment, and end-times prophecy, etc., in a systematic way. It's a gathering of all that the bible says on a subject and gaining a holistic understanding of it. A typical breakdown is shown below.

Though initially I was planning on writing the content for the subject matter below, I came to my senses, as it were, and determined it would be best to direct your attention to other's writings. Their works far surpass anything I could produce or articulate. And all, as pronounced by them, is to the Glory of God. So for each category below there will be a seperate page with multiple links to multiple men and maybe a short commentary by me interspersed.