Barbara Goldsmith, a best-selling writer who chronicled high-society contretemps including the custody dispute over “poor little rich” Gloria Vanderbilt in the 1930s, unveiling the wealthy and famous as often empty and unhappy, died June 26 at her home in New York City. She was 85.

The cause was congestive heart failure, her assistant Jeremy Steinke said.

Goldsmith was a founding editor of New York magazine, a contributor to publications including Vanity Fair and the New Yorker and the author of four nonfiction books. Her work combined historical sleuthing and social commentary, and it reflected both her experience — and wariness — of wealth.

A daughter of a moneyed real estate investor, Goldsmith said she recognized early on the drawbacks, even dangers, of fame. She said that like Vanderbilt — the railroad and shipping heiress who became a maven of designer jeans — she was scarred by the kidnapping and murder in 1932 of aviator Charles Lindbergh’s young son.

“I used to go to bed at night and wait for the sound of the ladder plopping against my bedroom window,” she once told the New York Times. “I’ve since found that a lot of people who grew up during the Depression had these same fears, because of the Lindbergh baby’s kidnapping.”

Goldsmith became fascinated by the Vanderbilt case four decades after the fact, while researching her first book, The Straw Man (1975), a novel that turns on the contested estate of a New York art collector. Working in a library, she stumbled upon 8,000 pages of court transcripts from the 1934 custody challenge that made 10-year-old Vanderbilt one of the most famous children in the United States.

The case involved the girl’s widowed mother, Gloria Morgan Vanderbilt, and an aunt, Gertrude Vanderbilt Whitney, who ultimately obtained custody. Their war over “little Gloria,” which riveted Depression-era Americas with lurid revelations of the family’s dissolution, became the subject of Goldsmith’s best-selling volume Little Gloria … Happy at Last (1980).

Goldsmith said that she trekked to seven countries for the book and interviewed 300 sources, although not Gloria Vanderbilt, who declined to participate. The book became a 1982 TV miniseries featuring Angela Lansbury, Christopher Plummer and Maureen Stapleton.

Little Gloria is like a Bruegel canvas, teeming with characters and events all moving in different directions,” Brigitte Weeks, a Washington Post editor, wrote in a review of the volume. “But even though she gives us a ten-course banquet of Vanderbilts and Whitneys, we are left — hard to believe — wanting more.”

Her marriages to C. Gerald Goldsmith, an investment banker, and Frank Perry, a filmmaker, ended in divorce. Survivors include three children from her first marriage, Andrew Goldsmith of Beverly Hills, California, Alice Elgart of New York City and John Goldsmith of Santa Monica, California; and six grandchildren.

Goldsmith described herself foremost as a “social historian.”

“The reason I write books,” she told the Times, “is an obsession to see that our society straightens out. We live in a world that is interested only in images and not reality, and I want to shatter those images — real heroes lead very tough, ascetic lives. But Americans are beginning to want to see behind these images, and I want to fight for this.”