In September, Rupert Murdoch ceded direct control of Fox and News Corp to Lachlan Murdoch, his oldest son. At 92, Rupert became chairman emeritus. He is off the stage but remains in the wings. From there, he can peer over his boy’s shoulder without saying goodbye. Synchronously, the Fox-watcher and Trump-chronicler Michael Wolff delivers The Fall: The End of Fox News and the Murdoch Dynasty, a bookend to The Man Who Owns the News, published in 2008. Wolff says he may be “the journalist not in his employ who knows [Murdoch] best”. In his new book, he aims to demonstrate...