“We condemn this brazen abuse of Mr Mandela’s name. We will be taking appropriate action,” his Nelson Mandela Foundation said in a statement.
The Congolese president took power in a coup and, after losing an election, regained it by winning a civil war. The foreword praises Sassou-Nguesso as “one of our great African leaders”.
“One of those who gave their unconditional support to our fighters’ demand for freedom, and who worked tirelessly to free oppressed peoples from their chains and help restore their dignity and hope,” it says.
The bookselling website Amazon says the semi-autobiographical Straight Speaking for Africa was published in English last month by Red Sea Inc of Africa World Press.
Michel Lafon first published the book in French earlier in the year. The Paris-based publisher said Sassou-Nguesso had provided the preface and offered no further comment.
Sassou-Nguesso’s office has not commented.
The Nelson Mandela Foundation said the former South Africa president had “neither read the book nor written a foreword for it”.
The foundation said the name of Mr Mandela, who is often referred to by his clan name Madiba, has been frequently abused for commercial gain. “This is one of the grosser examples with a direct impact for Madiba’s legacy,” the foundation’s Verne Harris is quoted by the UK’s Daily Telegraph newspaper as saying. — BBCOnline.