The Case For and Against Natural Law by Russell Kirk.

"The most important early treatise on natural law is Cicero's De Re Publica. The Ciceronian understanding of natural law, which still exercises strong influence, was well expressed in the nineteenth century by Froude: "Our human laws are but the copies, more or less imperfect, of the eternal laws so far as we can read them, and either succeed and promote our welfare, or fail and bring confusion and disaster, according as the legislator's insight has detected the true principle, or has been distorted by ignorance or selfishness."