This work contains a nice summary of atonement theories from the perspective of a progressive Christian. If the dominant Evangelical model of Penal Substitutionary Atonement doesn't seem to you like the only or best illustration of God's saving work in Jesus, this book is a worthwhile read.

It is approachable, having begun its life as a blog series. It is not particularly technical, but it is helpful for curious Christians who wish to broaden their understanding of historical developments in atonement theory and the models we have developed to illustrate them.