Isaiah Sheffer, who three decades ago looked at a grimy, derelict movie theater on Manhattan’s Upper West Side and envisioned the palace of performing arts that became Symphony Space, a vibrant, eclectic institution known for its broadcasts of actors reading short stories, died on Friday in Manhattan. He was 76.

The cause was complications of a stroke, his wife, Ethel, said.

The stage was part of Mr. Sheffer’s life even before he was born; he was still in his mother’s womb when she appeared in a Yiddish play. He went on to an exuberantly varied theatrical career as a librettist, playwright, director and impresario.

But he said his professional life had “no coherence” until he and his artistic partner, the conductor Allan Miller, put on a marathon concert of Bach at the theater on Jan. 7, 1978. The next morning, he wrote down his idea for a place he had decided to call Symphony Space, in part because that was the name of the theater and in part because its first event was a symphony concert.