The book, on the other hand, has been revised since Sondheim’s death by its writer, David Ives, and director, Joe Mantello. But the team said that “the three collaborators agreed after the informal reading that took place on Sept. 8, 2021, that Steve’s songwriting for both acts was complete.”

There is a long history of work in various stages of completion being released after the death of an artist. Mozart’s Requiem, Puccini’s “Turandot” and Berg’s “Lulu” were all left unfinished when their composers died and are now considered classics.

“The work that David and Stephen did should absolutely be seen,” said Oskar Eustis, the artistic director of the Public Theater, which was working with Sondheim to develop the show until a few years ago. “It’s a jewel, it’s small, it’s incomplete, but it’s absolutely delightful and smart and gorgeous, and it would be a crime for it not to be seen. So I’m entirely in favor of the work being shown in public.”

James Lapine, who as a librettist collaborated with Sondheim on shows including “Into the Woods” and “Sunday in the Park With George,” agreed. “I really trust David and Joe, and don’t think they would be putting up something they didn’t feel was finished — not on this scale,” he said. “They’re smart cookies, and if they wanted to do a workshop because it wasn’t finished, they could. But they see it as finished, and Steve gave his blessing, so it’s going to be an addition to the canon.”

The show, in Sondheim’s pithy description in that last interview, has a “so-called plot” in which “the first act is a group of people trying to find a place to have dinner, and they run into all kinds of strange and surreal things, and in the second act, they find a place to have dinner, but they can’t get out.”