Dr. J, a.k.a. Jason Jewell, has a nice discussion of the second chapter of my book on his blog The Western Tradition. He provides a nice summary of the chapter and some commentary on the issues raised.
Chapter 2 is devoted to an exposition of the general principles of human action. The foundations of economic analysis lie in the general principles of action, because all human interaction--the subject of economics proper--is human action. Economics, therefore, begins by identifying principles that apply to all action and that, therefore, apply to action in exchange. The law of marginal utility, for example, is a law that applies to all action and undergirds the economic laws of supply and demand.
Dr. J., by the way, is a model for all who desire to know more about the created order for the glory of God. He is in the middle of taking his readers through a seven-year great books reading project as well as having just embarked on an economics reading project.