When Mr. Trump discharged his first round of spite tweets, Ms. Kelly’s husband, the novelist Douglas Brunt, demanded to know what Fox was going to do. She writes, “I told him the truth: ‘Nothing for now.’” Instead, the network tried appeasement. “Roger was talking to Trump daily,” she adds, “trying to calm him down.”

It turns out that Mr. Trump and Mr. Ailes have a number of things in common, besides their politics. Both are 70-something tycoons. Both are obsessed with loyalty, thin-skinned and fragile. And both face accusations of sexual harassment from a number of women. The anchor Gretchen Carlson was the first to make this claim in public against Mr. Ailes. But she was by no means the only one. As Radar Online has already reported, Ms. Kelly confirms in her memoir that about a decade ago, she, too, was on the receiving end of Mr. Ailes’s advances.

She declines to get into many specifics, apart from his conjecture about the “very sexy bras” she must own and how he’d like to see her in them. “But suffice it to say, he made sexual comments to me, offers of professional advancement in exchange for sexual favors.” In 2006, she writes, Mr. Ailes tried to grab her and kiss her on the lips. Ms. Kelly dodged him twice and made a beeline for the door — at which point, she writes, he asked her an ominous question: “When is your contract up?” Then he lunged for the third time.

She consulted a lawyer. “But I knew the reality of the situation,” she continues. “If I caused a stink, my career would likely be over.”

Years later, when Ms. Carlson made her allegations against Mr. Ailes, Ms. Kelly was asked to speak in support of him. When she refused, Mr. Ailes “engineered hit pieces about me online,” she writes.

“I realized,” she continues, “I had a choice to make.” She could be quiet. Or: “I could ensure that the owners of Fox News Channel — Rupert Murdoch and his sons — understood they might actually have a predator running their company.”

She chose to call Lachlan Murdoch, executive co-chairman of News Corporation and 21st Century Fox.

Throughout the 2016 election, Ms. Kelly questioned Mr. Trump and his surrogates about the sexual harassment and assault accusations rapidly accumulating against him. But her memoir is a reminder that she is a complicated feminist figure — starting with the fact that she rejects the label “feminist.” The needle she threads has an almost microscopic eye. She is trying simultaneously to appeal to both her new “Lean-In” fan base and the regular Fox news watchers who abhor identity politics.