In brief, Covenant Theology teaches that God has established two great covenants with mankind and a covenant within the Godhead to deal with how the other two relate. The first covenant in logical order, usually called the Covenant of Redemption, is the agreement within the Godhead that the Father would appoint his son Jesus to give up his life for mankind and that Jesus would do so (cf. Titus 1:1-3).
The second, called the Covenant of Works, was made in the Garden of Eden between God and Adam and promised life for obedience and death for disobedience. Adam disobeyed God and broke the covenant, and so the third covenant was made between God and all of mankind, who also fell with Adam according to Romans 5:12-21.
This third covenant, the Covenant of Grace, promised eternal blessing for belief in Christ and obedience to God's word. It is thus seen as the basis for all biblical covenants that God made individually with Noah, Abraham, and David, nationally with O.T. Israel as a people, and universally with man in the New Covenant. These individual covenants are called the "biblical covenants" because they are explicitly described as such in the Bible.