Robin Denselow profiles the musician Youssou N'Dour as he reaches his 50th birthday, and travels to Senegal to interview the singer in his home city of Dakar. Denselow analyses not just his music but the way N'Dour has used it for the benefit of his country and his continent. He had huge success with the duet 7 Seconds with Neneh Cherry in 1994, but he has been making music for nearly 40 years and has collaborated with many international artists. Contributors include Peter Gabriel, Branford Marsalis, DJ Charlie Gillett and Senegalese band Orchestra Baobab. A Unique production for BBC Radio 4.