Gary Cohen and his nonprofit, Health Care Without Harm, have persuaded hospitals around the world to close their medical-waste incinerators, dramatically cutting emissions of dioxin and other toxins.
University of Georgia professor William Kisaalita engineers simple, practical solutions — a milk chiller, a nutcracker and an egg incubator — for Africa's rural poor.
University of Washington researcher Julia Parrish founded COASST, a nonprofit that allows hundreds of citizens to serve science by cataloging dead birds on West Coast beaches.
With few resources but the force of his title — U.N. special rapporteur on extrajudicial executions — Philip Alston holds governments accountable for the politically motivated killings they commit, or ignore.