Letitia Baldrige, an etiquette maven who served as social secretary to first lady Jacqueline Kennedy and later wrote books and a syndicated column advising readers on good manners in contemporary America, has died. She was 86.

Baldrige died Monday at a nursing facility in Bethesda, Md., said Mary M. Mitchell, a longtime friend and writing collaborator. Baldrige had severe osteoarthritis with cardiac complications.

In 1960, Baldrige had received a life-changing phone call from Jacqueline Kennedy, a friend from their days at a private girls’ school in Connecticut, who asked if she could help out at the White House. In her new role, Baldrige would come to arrange and oversee the glittering state dinners and other stylish social gatherings for which the Kennedy White House became known.