She was born Marcia Weinraub on June 10, 1939, in the Bronx to Dorothy (Lautman) and Ralph Weinraub, a real estate agent known as Lefty. She attended New York University for three years, studying retailing and journalism (and winning Miss New York University in 1959).
She worked as a buyer and fashion director for Gimbels department store, among other emporia, and then opened a funky clothing boutique, Abracadabra, on the Upper East Side in the late 1960s, the decoration of which involved a mirrored erector-set contraption salvaged from an old amusement park. She met her longtime partner, Chris Flanders, an actor turned contractor formerly named Christian Van der Put, when he helped her build a display for the store. He didn’t think the name Marcia fit her; to him, she was more of an Annie. So she adopted that name, along with his last name, though they never married.
In 1988, Details was bought by Advance Publications, the publishing empire of the Newhouse family, which owns Vogue, among other glossy titles, for a reported $2 million. Jonathan Newhouse was its publisher that first year, before moving to Paris in 1989 to oversee the company’s international titles.
Despite its popularity and influence, Details struggled financially, though at the time of its sale it had a paid circulation of 100,000. Ms. Flanders was fired two years later, and the magazine was reimagined as a men’s publication, with James Truman, a former Vogue editor, as its editor in chief. The magazine was closed in 2015.
In the 1990s, Ms. Flanders and her family moved to Hollywood, where she reinvented herself as a real estate agent, though she did not drive, working with her daughter, Rosie, who did. Her daughter survives her. Mr. Flanders died in 2007.
Decades never end neatly, and the ’80s were no exception. B 1989 the ranks of the downtown world that Ms. Flanders had so lovingly chronicled had been decimated by AIDS. Ms. Mueller died that year, as did thousands more.
“We thought it would last forever,” said Mr. Musto. “We thought the magazine would last forever.”