Bill Gates

Stephen Sackur travels to Geneva, currently hosting the World Health Assembly, to meet the world's most influential philanthropist, Bill Gates.

The founder of Microsoft is currently reckoned to be the world’s second richest man.

His Gates Foundation spends roughly $3bn a year on global health and development projects.

His drive and vision transformed the world of computing, but what kind of a difference can he really make in the global fight against disease and child mortality?