In the twentieth century the Reformed tradition was developed in several ways including additional confessions (Barmen, the Belhar Confession, the 1967 Confession of the PC(USA), and so on). It was also significantly augmented by the work of important thinkers like Karl Barth, T. F. Torrance, Jürgen Moltmann, Emil Brunner, Kathryn Tanner, and so on.

The atonement chapter [from the book Saving Calvinism] shows how there are real riches in Reformed theology that most Christians today have no idea about.

I think everyone who has an interest in Reformed theology, or just in Christian theology more generally, should read John Calvin Institutes.

Here is the interesting twist:[McLeod] Campbell came to his views through reading Jonathan Edwards who suggested at one point in his ruminations on the atonement that Christ could have offered up a perfect act of penitence instead of punishment, and that this would have been an acceptable offering suitable to remit our sinfulness.

[ Jonathan] Edwards is the person who really made theological determinism a serious option for Reformed thinkers, and the influence his views had in nineteenth century Reformed thought, in the USA and the UK in particular, is enormous.

The book [Saving Calvinism] argues in each case that the Reformed tradition is broader and deeper than we might think at first glance - not that there are people on the margins of the tradition saying crazy things we should pay attention to, but rather that there are resources within the "mainstream" so to speak, which give us reason to think that the tradition is nowhere near as doctrinally narrow as the so-called "Five Points of Calvinism" might lead one to believe.

In the chapter on the nature of the atonement [in the book saving Calvinism] I argue that it is a mistake to think that penal substitution is the only option on the doctrine of atonement.