Power’s Anna’s aphrodisiac,” a magazine staffer told author Jerry Oppenheimer for his 2005 book “Front Row: Anna Wintour,” a tell-all on what it was like being in Wintour’s orbit.

Anna Wintour made an announcement that shocked the worlds of fashion and media on Thursday: She will look for a new editorial lead to oversee the day-to-day operations of American Vogue, the ...