One autumn morning in 2001, Steve Reich was fast asleep at his home in rural Vermont. Shortly before 9am he awoke to the phone. It was his son Ezra calling from the family apartment in lower Manhattan, describing a chaotic scene unfolding just blocks away. A plane had just flown into the North Tower of the World Trade Center.

“It was a pretty wrenching experience,” explains the composer. “Basically I told him ‘don’t hang up’. The phone connection was open for six hours. I told him to get these little hardware store masks that we had in our bathroom and to put them on himself, his wife and our granddaughter, who was a baby at the time. Because I knew that outside was going to be chaos and full of debris and unbreathable materials.”

The family bundled into a neighbour’s car and, dodging road closures, somehow escaped to meet a relieved Reich in the country. Their New York apartment was so close to Ground Zero it fell within what the US Army called the “no-go zone”. It would be another month before they could return home safely.

These experiences have become the...