This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book addresses two theoretical issues critical for understanding China's South China Sea (SCS) policy. It investigates the People Republic of China's original claims to the South China Sea disputes as well as the competing claims of Vietnam and the Philippines, which provides a useful starting point from which we can track the transformation of the South China Sea disputes and the evolution of China's policy towards the South China Sea. The book examines how China's participation in the third law of the sea conference and other maritime organizations affected the leadership's perception of the South China Sea disputes, changed its calculation of maritime interests, and expanded its knowledge of ocean governance. It traces the learning and adapting process through which Chinese decision-makers gradually comprehended the new face of the SCS disputes.