Daniel Bell, 91, author, influential sociologist

NEW YORK - Daniel Bell, 91, a leading sociologist of the last half-century who wrote groundbreaking books about the demise of revolutionary politics and about the economy and lifestyle of what he helped label a "post-industrial" society, died Tuesday at his Cambridge, Mass., home after a short illness.

Mr. Bell was a teen radical who became an apostle of pragmatism. He is credited with two seminal works: The End of Ideology, which predicted a post-Marxist, post-conservative era, and The Coming of the Post-Industrial Society, in which he foresaw the shift from a manufacturing economy to one based on technology.

"Many people would testify to his influence, and I am one of those," said Nathan Glazer, a fellow sociologist. ". . . Some of his ideas about what was happening to society were very much on target."

Mr. Bell's books included Work and Its Discontents, The Reforming of Education, and The Cultural Contradictions of Capitalism, which explored how a bourgeois economy coexisted with an antibourgeois culture.

For decades, he was a public intellectual. He was a widely quoted essayist; a coeditor of the Public Interest, a founding neoconservative journal; and a professor of sociology at Harvard University and Columbia University, where he helped mediate a campus rebellion in 1968.

His influence sometimes reached the White House. In 1979, The Cultural Contradictions of Capitalism helped inspire pollster Patrick Caddell to have President Jimmy Carter give an address on the country's apparent spiritual crisis. It became known as the "malaise" speech.

Although Mr. Bell was linked politically to Public Interest cofounder Irving Kristol, he left the magazine after a few years and followed no single line of thinking. He believed in free elections and a regulated economy, but also valued cultural and moral tradition and scorned contemporary art. He defined himself as a liberal in politics, a socialist in economics, and a conservative in culture.

He briefly attended Columbia as a graduate student but dropped out to write for the New Leader, a liberal journal.

In the 1940s, he served as managing editor of the New Leader and as labor editor of Fortune magazine.

He wrote essays throughout the 1950s that were collected for The End of Ideology, published in 1959 and the source of debate for years. He believed that the disasters of Stalin and the Nazis and the rise of the welfare state had made extremism of both left and right obsolete. He predicted an era of more practical dreams based not on theory but on experience.

The Coming of the Post-Industrial Society, published in 1973, was a "venture in social forecasting" that anticipated an economic shift from muscle to knowledge, from horse power to brain power, from "a goods-producing to a service economy."

In 1980, he would call the new society "an information society" and foresee "the emergence of a new social framework of telecommunications" that would determine "the way knowledge is created and retrieved, and the character of the occupations and work in which men engage."