Wendell D. Garrett, a historian and authority on American decorative arts who was widely known for his appearances as an appraiser on the long-running PBS series “Antiques Roadshow,” died Nov. 14 at a hospice facility in Williston, Vt. He was 83.

His former wife Elisabeth Garrett Widmer confirmed his death.

Known for his broad expertise, a courtly manner and his delight in sharing knowledge, Mr. Garrett appeared on every season of the American version of “Antiques Roadshow” since its launch in 1997. He will also appear on the show’s next season, which was filmed last summer and premieres Jan. 7.

Mr. Garrett wrote and edited many books on antiques and American style, including “Victorian America: Classical Romanticism to Gilded Opulence” (1993), “Monticello and the Legacy of Thomas Jefferson” (1994) and “American Colonial: Puritan Simplicity to Georgian Grace” (1995).

He was also associated for many years with Sotheby’s, where he was a senior vice president in the American decorative arts department. From 1972 to 1990, he was editor of the Magazine Antiques and remained an editor at large for the fine-arts publication until his death.

“Wendell was the public face of American decorative arts and its interface with American history,” said Morrison Heckscher, chairman of the American wing of the Metropolitan Museum of Art in New York and a longtime friend.

“He was a felicitous writer, whether he was writing about antiques or historical figures, and he was an accomplished, compelling speaker,” Heckscher said. “He also had a remarkable ability to connect and empathize with people.”

On “Antiques Roadshow,” which sends experts across the country to appraise art and collectibles brought in by the public, Mr. Garrett handled a range of objects. Among his on-air assessments: a copper kettle for making apple butter (appraised at $2,000); a circa-1850 mosaic-topped table ($8,000) and a 19th-century cabinet decorated with stuffed songbirds (he appraised it at up to $11,000 and gently advised the owner to take care handling it, saying the birds may have been preserved with arsenic.)

Mr. Garrett hadn’t always been headed for the world of art and antiques.

Wendell Douglas Garrett was born in Los Angeles on Oct. 9, 1929. He attended the University of California at Los Angeles and, until he encountered organic chemistry, planned to become a doctor, Widmer said. He switched to history, earning a bachelor’s degree.

He then enrolled at the University of Delaware, receiving a master’s degree from its renowned Winterthur program in Early American culture. He later earned a second master’s degree in American history from Harvard.

In 1959, he joined the staff of the Adams Papers Project at the Massachusetts Historical Society, which edits and publishes letters and other papers of President John Adams, his wife, Abigail, and their descendants.

Mr. Garrett was assistant editor of “Diary and Autobiography of John Adams” (1961), a four-volume set that begins with diary entries from 1755.

But in 1965, on vacation in Vermont with his first wife, Jane N. Garrett, he was perusing documents at the Vermont Historical Society when he made a remarkable discovery: He found an even earlier Adams diary, hidden in the papers of a former suitor of John Adams’s daughter. “He was so excited he was almost airborne,” Jane Garrett said.

“The Earliest Diary of John Adams,” with entries beginning in 1753, was published in 1966, with Wendell Garrett as associate editor, along with Marc Friedlaender.

In all his work, Mr. Garrett often said that antiques and decorative objects offered a window into American social history and should always be viewed in context.

“Artifacts are three-dimensional documents that should be read like letters and public papers. They are a record of the people,” he said in a 1995 interview with the Chattanooga Free Press. “If antiques are treated as documents, our views and interpretation of the past are broadened, allowing people without a voice to speak.”

Mr. Garrett was twice divorced. Survivors include three children from his second marriage; a brother; and four grandchildren.

— Los Angeles Times