The Sino-British Joint Declaration was signed in 1984 and transferred control of Hong Kong to the People's Republic of China from the 1st July 1997. This sets the scene for the establishment of the Special Administrative Region (SAR) in Hong Kong, which has been at the heart of the civil unrest in 2019-2020, culminating in the National Security Law on 30 June 2020. In the 25th anniversary year of the handover of Hong Kong, C. L. Lim uses British archival sources to re-examine the Joint Declaration, the negotiations that led up to it, and its resounding significance that continues to the present day. Beginning with Margaret Thatcher's preparations for her Beijing trip, the book takes a chronological approach and offers a valuable, single-volume history of the Joint Declaration. In light of tumultuous current events in Hong Kong, Lim provides a vital, clear explanation of the legal complexities that have underpinned the relationships between China, Hong Kong and Britain since 1979.