In The Rome Statute as Evidence of Customary International Law, Yudan Tan offers a detailed analysis of topical issues concerning the Rome Statute of the International Criminal Court as evidence of customary international law. The 1998 Rome Statute has generated a great deal of scholarly interest. Providing a novel way of analysing the treaty-custom interactions, Yudan Tan examines the customary status of essential parts of the Rome Statute. Based on a flexible two-element identification approach, focusing more on opinio juris, Yudan Tan convincingly argues that provisions of the Rome Statute were partly declaratory of custom when adopted in 1998, and that they are also partly declaratory of custom at the present time.