On Saturday, 13 July 1985, a blazing, cloudless summer day, millions of people settled in front of the television. It was just before noon in London, 7 AM in Philadelphia, and around the world, it was time for Live Aid. This pair of huge concerts had been arranged in fewer than four months by singer and activist Bob Geldof of The Boomtown Rats: from a standing start to sixteen hours of music, seventy-plus artists and close to two hundred songs. These...