This chapter first provides the conceptual preamble to the other sections to enable a deeper understanding of the meaning and function of the space that is the region. The second section is an attempt to historicise the gradual formation of the idea of an Asia-Pacific region in the Cold War context. The third section proceeds to explore the reasons how and why the emphasis on an Asia-Pacific region shifted to the idea of an Indo-Pacific region. The fourth section explores the ways in which the Indo-Pacific region has been imagined into existence and how competing geographic imaginations challenge this new spatial classification. This will be demonstrated later in the chapter, when we look at the significance of Australia and India in the construction of the Indo-Pacific region. The next section argues that the post-Cold War period did not so much signal a period of regional extinction but that China's rise rather compelled a new round of regional reterritorialisation.