Ms. Kelly writes that her problems started in August, the Monday before the first Republican presidential primary debate. She had just done a segment on her show, “The Kelly File,” that infuriated Mr. Trump. He refused to make his own scheduled appearance on her show unless she phoned him personally.

“I almost unleashed my beautiful Twitter account against you,” she says he told her, “and I still may.”

Then, the day before the first presidential debate, Mr. Trump was in a lather again, Ms. Kelly writes. He called Fox executives, saying he’d heard that her first question “was a very pointed question directed at him.” This disconcerted her, because it was true: It was about his history of using disparaging language about women.

She doesn’t speculate where the leak came from. (She reports. You decide.) But that’s another unambiguous takeaway from this book: Parts of Fox — or at the very least, Roger Ailes, the network’s chairman until July, when he was given the boot after several allegations of sexual harassment were made against him — seemed to be nakedly colluding with the Republican presidential nominee.