Globalization means that ideas, people, resources—and germs—now move unfettered from country to country with great speed. On balance, this is good news for the health of populations around the world. But globalization also raises ethical questions about the conduct of clinical research in developing countries, use of clinics abroad to train U.S. medical students, lack of essential medicines by many who need them, and migration of doctors from low-income countries to those with higher standards of living. July's contributors—many with international medical experience—take up these questions and more.