An insular Possession is a novel that concerns the Opium War which led to the colonization of Hong Kong. Through the experience of two Americans, Gideon Chase and Walter Eastman in China, this episode is vividly presented. This novel was short-listed for the Booker Prize, and in 1992, Timothy Mo received the E.M. Foster Award from the American Academy of Arts and Letters. The aim of this thesis is to make a comparison between the novel and the historical archives in order to find out Mo's pattern of selection and fictionalization as well as the ways he uses in narrating his novel. Four aspects will be examined: characters, places, events and miscellaneous items. The results show that this novel enriches historical facts. However, Mo makes use of different writing techniques to present them. Readers do not feel that they are reading a historical book. In regard of the references, five history books and four historical newspapers are used. However, the main sources for this thesis are the Journal of Harriett Low and the Chinese Repository which is a quarterly paper published in Canton and Macao. The findings in McLeod's article 'On the Chase for Gideon Nye: History and Representation in Timothy Mo's An Insular Possession will be the basis of analysis for the chapter of characters.