The Law of the People's Republic of China on Safeguarding National Security in the Hong Kong SAR (the "NSL") promises to be the most important legal development in Hong Kong since the advent of the Basic Law. Many wondered in the aftermath of the NSL how the foundations of Hong Kong's system might be changed and in what way the freedoms valued by Hong Kong may be affected. Supporters view the law as essential for the preservation of public order and the national security of China and for supporting the fundamental well-being of "One Country, Two Systems", an arrangement that has been in place since the return of Hong Kong to China. Critics fear an adverse impact on the spirit of "One Country, Two Systems".

From a discussion initiated by the University of Hong Kong's Faculty of Law, this collection of essays brings together leading experts on Hong Kong and Chinese law to offer an exploratory study of the NSL and its impact on the legal system and the principle of the rule of law in Hong Kong.

The book examines the ramifications of the law in relation to constitutional matters, protecting national security and sustaining "One Country, Two Systems", policing, judicial independence, and extraterritoriality, as well as its wider implications in areas such as academic freedom and the business environment. It explores the interaction between Hong Kong and Chinese law occasioned by the NSL. Finally, the book offers a comparative perspective of the experience of other jurisdictions that have engaged with similar security legislation.