Rayner Kay Jin Tan is a postdoctoral fellow at the University of North Carolina Project-China. He is also a visiting research fellow at the National Centre for Infectious Diseases in Singapore and the Saw Swee Hock School of Public Health at the National University of Singapore. He is a social scientist by training and his research interests are in the fields of community-based participatory research, sexual health and well-being, drug use and addiction, and mixed and qualitative research methods. He is also President of Project X and Chairperson at The Greenhouse Community Services Limited, which are community-based organizations serving sex workers and people who use drugs in Singapore, respectively.