NEW YORK — Philip Johnson, whose austere "glass box" buildings and latter-day penchant for incorporating whimsical touches in his designs made him one of the most influential architects of the 20th century, has died at 98.

He died Tuesday at his home in New Canaan, Conn.

Mr. Johnson's work, which spanned more than half a century starting in the 1940s, ranged from the modernism of his home, a glass cube in the woods, to the more fanciful work of his later years, including the AT&T Building in New York, with its curved pediment that made it look like a giant Chippendale chest of drawers.

Mr. Johnson once said his great ambition was "to build the greatest room in the world — a great theater or cathedral or monument. Nobody's given me the job."

In 1980, however, he completed his great room, the Crystal Cathedral in Garden Grove, Calif., a soaring glass structure wider and higher than Notre Dame in Paris.

With partner John Burgee, Mr. Johnson also designed the Bank of America building in Houston, a 56-story tower of pink granite stepped back in a series of Dutch gable roofs; and the Cleveland Playhouse, a complex with the feel of an 11th-century town.

"The world has lost a towering force who defined the art and practice of architecture in the 20th century," said architect Daniel Libeskind, the master planner for the new towers rising on the site of the World Trade Center.

"He was probably our first and most significant architect as celebrity," said Paul Goldberger, architecture critic for The New Yorker. "There's no question that he used his fame for the betterment of architecture."

Mr. Johnson also invented the role of museum architecture curator, at New York's Museum of Modern Art in 1932. And he coined the term International Style for the work of Europeans Ludwig Mies van der Rohe and Le Corbusier.

His efforts to bring their style to the United States and incorporate some of its elements in his own work "literally changed the landscape of American architecture," said Terrence Riley, MoMA's chief curator for architecture and design.

Mr. Johnson's AT&T Building, a granite-walled tower with an enormous, 90-foot arched entryway and a fanciful top, broke decisively with the glass towers that crowded Manhattan. The building, completed in 1983 and now owned by Sony, marked a sharp turn in architectural taste away from the clean lines of modernism.

Most of the firm's projects were corporate palaces: the Transco II and Bank of America towers in Houston, in 1983 and 1984; a 23-story neo-Victorian office building in San Francisco; and a mock-gothic glass tower for PPG Industries in Pittsburgh, built in 1983.

Toward the end of his life, Mr. Johnson went public with some private matters: his homosexuality and his past as a disciple of Hitler-style fascism. On the latter, he said he spent much time in Berlin in the 1930s and became "fascinated with power," but added he did not consider that an excuse.

"I have no excuse [for] such utter, unbelievable stupidity. ... I don't know how you expiate guilt," he said.

He said it was his homosexuality that caused him to suffer a nervous breakdown while he was a student at Harvard.

Philip Cortelyou Johnson was born July 8, 1906, in Cleveland, the only son of lawyer Homer Johnson and his wife, Louise. He graduated from Harvard in 1927 with a degree in philosophy, then toured Europe and became interested in new styles of architecture.

In 1940, Mr. Johnson returned to Harvard for graduate school, studying under Marcel Breuer. He returned to MoMA, then left in 1955 to open his own design office.

His projects at times ran into criticism from preservationists and even fellow architects. In 1987, he was replaced as designer of the second phase of the New England Life Insurance Co. headquarters in Boston after residents complained about the project's size and style.

But in 1979, Mr. Johnson became the first recipient of the prestigious Pritzker Architecture Prize.

Early in his career, he reflected on what he had hoped to achieve.

"I like the thought that what we are to do on this Earth is embellish it for its greater beauty," he said, "so that oncoming generations can look back to the shapes we leave here and get the same thrill that I get in looking back at ... the Parthenon, at Chartres Cathedral."