In 1976 composer Philip Glass and director Robert Wilson redefined opera with the debut in Avignon, France, of Einstein on the Beach. The nearly five-hour, non-narrative work broke a host of operatic conventions and would become the most celebrated of the many collaborations between these two giants of the musical and theatrical stage.

Now, Mr. Glass’s autograph score for the landmark work is coming to the Morgan Library & Museum as a bequest from the estate of the late New York collector and philanthropist Paul F. Walter. A longtime supporter of the Morgan who died in January 2017, Mr. Walter also bequeathed the museum scene designs and other items related to the work.