“A giant in modern political science, Sid Verba’s passion was to understand — and further — participatory democratic citizenship,” said Theda R. Skocpol, a professor of sociology and government at Harvard.

Professor Verba taught at Harvard for more than 30 years, until 2007, when he retired as university professor emeritus of government. He was the director of the Harvard University Library from 1984 to 2007 — longer than anyone since Thaddeus William Harris, who ran it for about 25 years in the mid-19th century.

“Sidney Verba excelled at not just one career but two,” said Professor Schlozman, who teaches political science at Boston College.

Sidney Verba was born on May 26, 1932, in the East Flatbush section of Brooklyn to Morris and Recci (Salman) Verba, Jewish immigrants from what is now Moldova in Eastern Europe. They ran a curtain store but were always worried about money. His parents also worshiped Franklin D. Roosevelt.

“I did not meet a Republican until college,” Professor Verba once said.

He enrolled at Harvard after graduating from James Madison High School in Brooklyn. “It took me six months to realize that perhaps I did not belong there,” he said of the Cambridge campus, “by which time I felt I belonged.”

He graduated in 1953 with a degree in history and literature, having taken only one government course. He then enrolled in the Woodrow Wilson School of Public and International Affairs at Princeton, where he earned a master’s degree and his doctorate in politics.

He married Cynthia Winston, a fellow counselor he had met at a summer camp. She became a musicology scholar and director of fellowships for Harvard’s Graduate School of Arts and Sciences.