The pianist confronts an embarrassment of riches. To a performer embarking on a concert career, five centuries of keyboard music beckon, with every phrase of every prelude and fugue, every sonata and partita, mazurka and minuet, impromptu and intermezzo, rhapsody and fantasy and scherzo and concerto — the hundreds of thousands of pieces the repertory comprises — open to an array of possible interpretations.

To this vast storehouse of ebony-and-ivory treasures, Joseph Bloch was a learned guide for thousands of young pianists, many now among the finest alive. And though he indelibly shaped world-famous performers for nearly half a century, Bloch did so almost entirely without giving private lessons.

Bloch, who died March 4 at 91, was a professor of piano literature at the Juilliard School in New York. His death, at his home in Larchmont, N.Y., was the result of a heart attack, his family said.

For five decades (with an interruption in the 1980s when he tried to retire but proved indispensable and was persuaded to return), every Juilliard pianist passed through Bloch’s classroom. His pupils included many of the best-known performers of the second half of the 20th century, among them Van Cliburn, Emanuel Ax, Garrick Ohlsson, Misha Dichter, Jeffrey Siegel and Jeffrey Swann.

“I went through the undergrad, grad and doctoral-level courses here, so I took just about every course he taught,” Yoheved Kaplinsky, the current chairwoman of Juilliard’s piano department, said in a telephone interview Thursday. “Many, many other pianists, even though he didn’t teach them privately, felt that he had an immeasurable impact on their musical knowledge and their musical scope.”

Bloch’s wife, the former Dana Kendrick, whom he married in 1944, died last year. He is survived by a daughter, Leslie Gordon; two sons, John and Andrew; a sister, Frances Julian; and seven grandchildren.