Papua New Guinea (PNG) occupies the eastern half of the island of New Guinea and is geographically the largest country of the Pacific region. This chapter focuses on a research study that was conducted early in the second phase of PNG's largest HIV prevention project; after an independent evaluation of the first phase of the project concluded that the project appeared to have lost its conceptual focus'. A social mapping' exercise was conducted by the new managers of the second phase of the project. The chapter focuses more on the people who move through the environments where sex is trans acted and where people are drinking and partying, which are often the same places. Social and anthropological research on HIV and sex conducted in PNG since the first Tingim Laip Social Mapping study pointed to the need to move away from a research focus on people's knowledge, attitudes and behaviours.