Howard Hughes Medical Institute: The largest private source of medical research funds in the United States. The Institute is one of the world's largest philanthropies. It has medical research laboratories across the US and grants programs throughout the world. The Institute carries out medical research with its own scientific investigators, all of whom work in Institute laboratories while also serving as faculty members at their host universities. The Institute follows the principle of "people, not projects." It believes that science is facilitated best by providing outstanding researchers with the resources and flexibility to follow their scientific instincts and to pursue new opportunities as soon as they arise.