David Bowie appeared on the British Broadcasting Corporation dozens of times over the decades, showing him as both an unknown teenager and an icon of music - and the stages inbetween. Tom Hagler is the author of We Could Be: Bowie and his Heroes. A reporter on the BBC's World Service, Tom has conducted interviews with a wide range of politicians, musicians and cultural figures, with a roll call as diverse as President Joe Biden, Kofi Annan, Buzz Aldrin and Grandmaster Flash.