The current immigration debate in labour-importing countries such as Malaysia centres largely on whether migrants are an asset or a threat. On the one hand, migrant labour is an important economic asset in meeting labour shortages, keeping down labour costs and providing a range of skills not available locally. On the other, there are concerns that migrants put pressure on health and educational services and affect national security. It is also increasingly evident that many people move in disregard of the borders that delineate nations because they aspire to achieve a better life. This movement is perceived to undermine national structures since some migrants operate outside official channels and it is thus in local situations and contexts that the impact of migration is experienced, debated, and contested most directly. The current debate suggests that Southeast Asia is facing an important change of direction due to migration contributing to the reinvention and reconstruction of increasingly impenetrable borders. With the aim of contributing to this ongoing debate in Southeast Asia and the wider Asia-Pacific region, the Malaysia and Singapore Society of Australia addressed these and other issues at its Fourteenth Colloquium in December 2006. The Colloquium theme - Boundaries and Shifting Sovereignties: Migration, Security and Regional Cooperation In Asia - was tackled from a variety of perspectives. Seven papers from the interdisciplinary colloquium were selected for this special issue and provide new insights into the debates around migration and security in the region. In this volume we first examine migration issues focussing on state and societal perceptions towards migrant workers in Malaysia, the migration-trafficking-refugee nexus and the role of the Jesuit Refugee Service, a faith-based organisation that works with refugee groups in the Asia-Pacific. Second, in the context of rethinking about borders, we examine the key issue of security and how Malaysia in particular deals with regional security issues and conflict at its borders with Thailand and the Philippines. The question of suicide bombers in Indonesia is also considered in the wider context of national and regional security.