Slavery is thought by many to have been banished in an earlier age, but millions of people remain in forced labor around the world. Migrant workers, who account for some 60% of the world’s 244 million international migrants, are particularly susceptible to abuse, as are those trafficked and pressed into prostitution. Here are four journalists on the cutting-edge of reporting on this major human rights issue, reporting from Africa, Asia and Europe. The group includes an expert on tracking “supply chains” of goods produced by forced labor, and a member of last year's Pulitzer Prize-winning team that helped free 2,000 slaves in Indonesia.