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·西蒙（Yves R.Simon）法国哲学家，20世纪托马斯主义自然法理论复兴的旗帜性人物之一。在剑桥大学出版社出版的一本论述20世纪政治哲学的著作中，编者把西蒙视为与罗尔斯、哈贝马斯等齐名的18位最重要的20世纪政治哲学家之一。

杨天江，北京大学法律史博士，西南政法大学法理学教师，主要研究领域为法理学和西方法律思想史，特别致力于托马斯主义自然法理论研究。