Mr. Belsky learned to read when he was 5, and reading became a favorite pastime. For more than 30 years, he was a trustee and a member of the board of directors of the Free Library of Philadelphia.
Mr. Belsky combined a love of learning with a love of teaching, his wife recalled. As a young man in New York, he ran the library at the old Rand School of Social Sciences, which was dedicated to the social improvement of the working class, she said.
From 1935 until 1944, Mr. Belsky was education director of the International Ladies' Garment Workers Union in New York. For the next 10 years, he held the same position in Philadelphia.
Then he left the city and his work with the union to become secretary of the state Labor Relations Board in Harrisburg.
In 1962, Mr. Belsky became an arbitrator for the labor board, and in 1972 he was named its executive director. He held that post for four years until his retirement. But even after retirement, he continued to work as an arbitrator, his wife said.
"He was always concerned about people, about their living and working conditions. He came from a working family, and throughout his career he continued to give classes on arbitration and on improving working conditions," she said.
Surviving, in addition to his wife, are a daughter, Vera, and a brother.
Burial will be private. A memorial service will be held at a date to be announced.