In preparation for the peace conference that was expected to follow World War I, in the spring of 1917 the British Foreign Office established a special section responsible for preparing background information for use by British delegates to the conference. Macaois Number 81 in a series of more than 160 studies produced by the section, most of which were published after the conclusion of the 1919 Paris Peace Conference. Macau was at that time a colony of Portugal, leased by China to the Portuguese as a trading port. The book includes sections on physical and political geography, political history, social and political conditions, and economic conditions. The section on political history covers the arrival of the Portuguese in around 1515 and the development over the centuries of relations between China and the Portuguese colony. The section on economic conditions notes that the “industry of Macao is mainly in Chinese hands” and that the “chief industry is opium, which the colony imports raw (opio crù) and prepares for exportation (opio cosido).” The final chapter, “General Remarks,” notes that “Macao owes its whole importance to the fact that it is a port; but as such it cannot long remain of much value, for the harbour is being silted up by the alluvium brought down the Canton [Pearl] river….” Macau was returned to the People’s Republic of China (PRC) in 1999 and, along with Hong Kong, is one of two special administrative regions in the PRC.