This book presents original evidence of a previously undisclosed dark side to China's Hong Kong policy after 1982. It documents a covert program of immigration from the mainland to Hong Kong which was designed to put in place a classic fifth column of Communist loyalists to be used if all other institution-based arrangements for the power transfer of the British colony to Chinese rule failed. This finding is revealing and important in its own right as a contribution to study of the Hong Kong transition. But the book focuses more on the broader significance of the motivation of such a fifth column policy for both the study of Chinese foreign policy and international relations theory. Studies of international affairs regularly impute motives to states or their leaders. Yet, when it comes to analysis of the imputed motives, most scholars see that as nearly impossible given the difficulty of penetrating the minds of the individual leaders concerned. However, a small number of scholars have taken up the challenge. They believe that foreign policy motivation can be studied despite its apparent complexity and elusiveness. They see the study of motivation of a given foreign policy as the only way of grasping its essence and, therefore, of ascertaining clues about its future development. This book argues that motivation study advances our understanding of Chinese foreign policy. Drawing on an investigation of existing theoretical studies of motivation, it identifies and synthesises three approaches to the study of motivation that seem particularly relevant to the Chinese case: perception; personality; and structural/situational constraining factors. It also analyses the historical, political culture, ideological and structural sources of Chinese policymaking to illustrate how these three elements can elucidate Chinese foreign policy motivation. Its conclusion is then tested against the case of China's fifth column policy in Hong Kong. The findings from the Hong Kong case study reflect two parallel but contradictory lines of motivation in the reform era of Deng Xiaoping: a dynamic adjusting and learning process on the one hand, and a strenuous effort to retain its traditional practice on the other. The book concludes that, despite increasing pressures for adaptation from constant and tremendous changes in global and national settings, Chinese foreign policy motivation could not in the final analysis overcome the constraints imposed by its underlying doctrines and practices, which had been so firmly embedded in the minds of the Communist leaders that it became a traditional mode of responding to the unknown and uncertain culture of Chinese foreign policy.