The tradition of natural law is one of the foundations of Western civilization. At its heart is the conviction that there is an objective and universal justice which transcends humanity's particular expressions of justice. It asserts that there are certain ways of behaving which are appropriate to humanity simply by virtue of the fact that we are all human beings. Recent political debates indicate that it is not a tradition that has gone unchallenged: in fact, the opposition is as old as the tradition itself. By distinguishing between philosophy and ideology, by recalling the historical adventures of natural law, and by reviewing the theoretical problems involved in the doctrine, Simon clarifies much of the confusion surrounding this perennial debate. He tackles the questions raised by the application of natural law with skill and honesty as he faces the difficulties of the subject. Simon warns against undue optimism in a revival of interest in natural law and insists that the study of natural law beings with the analysis of the law of the land.He writes not as a polemicist but as a philosopher, and he writes of natural law with the same force, conciseness, lucidity and simplicity which have distinguished all his other works.

耶夫·西濛（Yves R.Simon）法國哲學傢，20世紀托馬斯主義自然法理論復興的旗幟性人物之一。在劍橋大學齣版社齣版的一本論述20世紀政治哲學的著作中，編者把西濛視為與羅爾斯、哈貝馬斯等齊名的18位最重要的20世紀政治哲學傢之一。

楊天江，北京大學法律史博士，西南政法大學法理學教師，主要研究領域為法理學和西方法律思想史，特彆緻力於托馬斯主義自然法理論研究。