First let me say that I am a Premillenialist and solidly so. I am also a Baptist and have no plans in advocating being Reformed or Presbyterian. Michael Horton likes to say he is Reformed with a capital "R." Both he and R. Scott Clark bitterly castigate Baptists that they start from scratch every generation. This introduction by Dr. Duncan does no such thing, instead he praises Baptist Mark Dever very highly who does not sprinkle babies and yet is a Covenant Theology adherent. For myself, I could be Reformed but with a small "r."
I have a pastor friend who is a long time Evangelical Free minister who holds to a weird practice that I often have seen amongst Dispensationalists: He is almost allergic to reading anything by an author who is not Premillenial (to minister and belong to the Free Church, one must be Premillenial). How sad! For two reasons: 1. He places his association to his group higher than being able to investigate the bible in a thorough manner. This reminds me of the Jews in Jesus' day who would not confess Him for fear of being put out of the synagogue. 2. If a doctrine is worth holding then it should be able to withstand arguments from all quarters to the contrary and he should know what the other side holds to and be better to defend it instead of hiding his head in the sand.
Anyway, to me, this is an invaluable article since it explains the big picture of the bible in a cogent and succinct manner and reviews some of the literature from Covenant Theologians (this alone makes it worthwhile and is very good). He also identifies the opponents of Covenant Theology and surprisingly enough the Dispensationalists are but a minor player. Neo Orthodoxy (Barth and his followers) is the real bitter enemy of CT.
The piece evidently has been reformatted for electronic dissemination but it is very easy to read and covers much ground. Ligon Duncan very clearly explains how covenants functioned in the bible and secular life. He expertly points out too (this was very helpful to me personally) that no covenant is wholly unilateral but is a relationship in its essence. The "will aspect" of a covenant in Hebrews is also explained about how it takes effect only at the death of the one who made it (9.17). All these topics are handled in a very flowing and logical style that reflects the deep understanding Dr. Duncan possesses and his ability to communicate it clearly.
If I could describe further, it would be seeing the forest and how the trees contribute to it. How God relates to fallen humans in the bible. One small errata which is insignificant: read "epoch" for "epic." Enjoy!