I am Professor in the Department of Community Health Systems and the Division of Prevention Science at the University of California, San Francisco, and a Senior Research Scientist at the San Francisco Department of Public Health. I have been conducting research on the intersection between substance use (i.e., alcohol, methamphetamine, cocaine, and opioids), and HIV, and intervention research studies among key populations at risk for HIV (i.e., men who have sex with men [MSM], transgender individuals, and people who use drugs) for 15 years.