Slavery may be illegal but it's by no means defunct (even if its guises have changed). More than 27 million people are still trapped in one of the world's oldest forms of oppression. Documenting Disposable People features newly commissioned photo essays by eight renowned Magnum photographers--Ian Berry, Stuart Franklin, Jim Goldberg, Susan Meiselas, Paolo Pellegrin, Chris Steele-Perkins and Alex Webb--on diverse instances of contemporary global...