This review explores certain challenges related to the notion of customary international law. It seems that it was a long time ago when international law academics and practitioners ever thought that the nature of this source was a well-settled topic. Nowadays international lawmaking processes involve an extraordinary number of interactions, taking place both formally and informally. Such complex features are reflected by an exponential increase in the scholarly study of international legal sources. The legal nature, its applicability and principles regulating customary international law are addressed in the book under review (Brian D Lepard (ed), Reexamining Customary International Law (Cambridge University Press 2017)) through several topical essays. The chapters offer a comprehensive analysis of these lawmaking processes and the challenges they portray from various perspectives and in various fields, such as: What is customary international law and why is it law? Is it law because it reflects a ‘global legislative’ model? What is the current value of the persistent objector theory? Is the two-element definition of customary international law still applicable? By meticulously addressing these and other inquiries, the book presents novel arguments and represents a stimulating addition to the literature on sources of international law.

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对国际法渊源理论的几点思考：重新审视习惯国际法

本综述探讨了与习惯国际法概念相关的某些挑战。似乎在很久以前，国际法学者和从业者就曾认为这一来源的性质是一个很好解决的话题。如今，国际立法过程涉及大量正式和非正式的互动。对国际法律渊源的学术研究呈指数增长反映了这种复杂的特征。法律性质、其适用性和规范习惯国际法的原则在所审查的书中进行了论述（Brian D Lepard (ed)，重新审视习惯国际法（剑桥大学出版社 2017 年））通过几篇专题论文。这些章节对这些立法过程以及它们从不同角度和不同领域描述的挑战进行了全面分析，例如：什么是习惯国际法，为什么是法律？是因为它反映了“全球立法”模式而成为法律吗？持久反对者理论的当前价值是多少？习惯国际法的两要素定义是否仍然适用？通过细致地解决这些问题和其他问题，本书提出了新颖的论点，并为有关国际法渊源的文献提供了令人振奋的补充。