As he struggled to write what would turn out to be his last musical—Here We Are—Stephen Sondheim turned to his friend of 45 years, the producer Cameron Mackintosh, for help. He was, he admitted, drying up artistically and was unable to complete the second act. “He was worried that what he’d written sounded like his other songs,” Mackintosh says. “He kept saying, ‘Haven’t I written that before?’ It was an excuse not to write.”

He turned to Mackintosh “because most of his friends and collaborators had died, and I was the only one left he could go through the show with, to hear my pluses and minuses.” Mackintosh did what good producers and friends do: he encouraged. He thought there were five “really good pieces of material” in what Sondheim had written up to that point and prodded him to get back to work. But it was not meant to be. Four days after their phone conversation, Sondheim came home from a Thanksgiving dinner with friends in Roxbury, Connecticut, and died, at age 91.