Two large, unnatural disasters helped to create the impetus for the field of environmental health to grow in scope. But before there was a U.S. Environmental Protection Agency and before the National Institutes of Health (NIH) included environmental health, there was the Kresge Center for Environmental Health at Harvard’s School of Public Health. Beginning in 1958, the center brought together medical and physical scientists and engineers to investigate the manmade health problems of the 20th century. From a classic focus on industrial workplaces, the Kresge Center has seen environmental health grow to incorporate every part of our natural and constructed habitats. And over the years the Center has added the expertises of epidemiology, biostatistics, and molecular biology to its scientific arsenal, allowing the assessment of environmental damage at the cellular level as well as the susceptibility of individuals to certain environmental hazards.