WASHINGTON — “Are you O.K.?” Andrew G. McCabe, the acting F.B.I. director, asked Rod J. Rosenstein, the deputy attorney general. It was Friday morning, May 12, 2017, three days after President Trump had summarily fired James B. Comey as the F.B.I. director. The conversation is described in a new book that portrays Mr. Rosenstein as anguished and isolated as he struggled with the realization that Mr. Trump might have ousted Mr. Comey to obstruct the F.B.I.’s investigation of Russian interference in the 2016 election — and that he would probably have to appoint a special counsel to take over the inquiry, even if it cost him his job. The book, “Deep State: Trump, the F.B.I. and the Rule of Law” by James B. Stewart, provides new details about the history-making interactions between top Justice Department and F.B.I. officials immediately after the president ousted Mr. Comey. It recounts how Mr. Rosenstein was so troubled by Mr. Trump’s behavior that he twice proposed that he secretly wear a wire and record the president in the White House, the second time in the presence of an F.B.I. official who took notes. Drawing heavily on reporting by The New York Times, Mr. Stewart, a Times rep...