Dr. Hartsock has worked in HIV/AIDS and related problems since the inception of the pandemic.  Interested in social, economic, and political impacts of these problems and how they can be mitigated.

He seveloped National Institute on Drug Abuse's AIDS research program.  Goes beyond AIDS and includes other problems, e.g., TB, STIs, hepatitis. In charge of a research grant program which includes cooperative international efforts (e.g., former Soviet Union, East Asia, Latin America, Africa).

Developed and administer largest extant AIDS (and related problems) modeling program which has produced research directly responsible for changing U.S. and international health policy, e.g., expanded HIV testing, circumcision, "HIV Superhighway" (concurrent sexual partnerships).

Dr. Hartsock has Co-authored Surgeon General's Report on AIDS with Dr. C. Everett Koop (awarded Surgeon General's Exemplary Service Medal for this and related work). He work with various federal, international, and NGO institutions, e.g., UNAIDS Task Force on AIDS in the Military.

Dr. Hartsock is committed to “health diplomacy” as one of the very best ways to further international cooperation, stability, and peace.