Nelson Mandela's family is no stranger to the public eye — its successes and trials have been aired for decades through books, films and the news media.

Granddaughter Zoleka Mandela's story, perhaps, is the one that no one saw coming. The 33-year-old launches a book in South Africa Tuesday, "When Hope Whispers," that recounts her family's involvement in the fight against apartheid, her struggles with alcohol and drug addiction, the loss of two of her children and her fight against breast cancer.

Zoleka says as a Mandela she has a social responsibility to make a difference, and hopes the book inspires those struggling.

The book's publication comes as Nelson Mandela, 95, is in critical but stable condition, under intensive medical care at his Johannesburg home.