This book offers an empirically rich study of Chinese nuclear weapons behaviour and the impact of this behaviour on global nuclear politics since 1949. China's behaviour as a nuclear weapons state is a major determinant of global and regional security. For the United States, there is no other nuclear actor -- with the exception of Russia-- that matters more to its long-term national security. However, China's behaviour and impact on global nuclear politics is a surprisingly under-researched topic. Existing literature tends to focus on narrow policy issues, such as misdemeanours in China's non-proliferation record, the uncertain direction of its military spending, and nuclear force modernization, or enduring opaqueness in its nuclear policy. This book proposes an alternative context to understand both China's past and present nuclear behaviour: its engagement with the process of creating and maintaining global nuclear order. The concept of global nuclear order is an innovative lens through which to consider China as a nuclear weapons state because it draws attention to the inner workings --institutional and normative-- that underpin nuclear politics. It is also a timely subject because global nuclear order is considered by many actors to be under serious strain and in need of reform. Indeed, today the challenges to nuclear order are numerous, from Iranian and North Korean nuclear ambitions to the growing threat of nuclear terrorism. This book considers these challenges from a Chinese perspective, exploring how far Beijing has gone to the aid of nuclear order in addressing these issues.