As the subtitle suggests, "Principalities and Powers" is a "Study in Pauline Theology." Yet, G. B. Caird's analysis goes far beyond the bounds of simply the Pauline evidence. The book, which is a collection of lectures, consists of four chapters, and most of them deal extensively with the Old Testament (and some Second Temple Jewish) background for Paul's thinking about the principalities and powers. It is not until the last chapter that Caird addresses Paul's notion of these powers at length.
Caird covers much ground in the limited space that is afforded him in this book. This book is a quick read (only around 100 pages) and Caird is a wonderful writer, stating things plainly and succinctly. Because the book is a collection of essays, it can feel somewhat disjointed at times, as though each chapter can stand alone. Even the final chapter does not tie up the loose ends or even necessarily put all the pieces together for a final portrait. I also do not agree with some of conclusions, especially his overtly negative portrait of the law (he seems to compare the Mosaic law to Satan himself!). Still, however, I would recommend this work to anyone interested in the topic. In regard to the New Testament understanding of the powers, Caird deserves to be read right alongside Walter Wink and Hendrik Berkhof.
This book is a collection of lectures that Caird gave on the subject of Paul's theology of the "principalities and powers." Each of the four chapters can be read separately without losing a lot of cohesion; each was a separate presentation in its own right.
Caird explores how the theology of the Powers grew out of both Hebrew and Greek thought and was influenced by the religions of other Middle Eastern cultures as well. From these influences and from the various references in the Apostle's own writings, Caird believes that Paul saw the Powers as being part of God's original creation, and thus subject to the Fall (corruption of sin) and in need of redemption or reconciliation.
Despite the scholarly and analytical nature of these lectures, Caird's work ultimately comes from a specifically orthodox Christian perspective. The final lecture discusses how Christ will overcome and ultimately redeem the Powers, using non-violent resistance as modeled for us by Christ's own obedience to the Cross. This work seems to be the forerunner of later scholars such as Yoder and Wink, who take this theme and explore it much more deeply.