During his 27 years in prison, Nelson Mandela’s most powerful tools were a pen and paper. His 18 years on the island—and remaining nine in Pollsmoor and Victor Verster prisons—were preserved in a series of strongly worded prison letters. While history remembers Mandela as a revolutionary leader, The Prison Letters of Nelson Mandela reveals a more personal side. Small Room, Big IdeasThe cell occupied by Nelson Mandela in Robben Island, South Africa. | Jeff Overs/GettyImagesAs a lawyer and activist, much of what Mandela wrote in his letters naturally centered on human rights.