In his book, “A Higher Loyalty,” Mr. Comey staunchly defends his actions during one of the country’s most polarized campaigns. He says that holding a news conference to clear Mrs. Clinton of mishandling emails was the right thing to do to protect the independent reputation of the F.B.I. He says that publicly reopening the email case 11 days before the election was a no-win situation, and argues that covering it up would have been worse.

“Speak or conceal — both terrible options,” he writes in the book, which is coming out on Tuesday. “No matter what we found, that act of concealment would be catastrophic to the integrity of the F.B.I. and the Department of Justice. Put that way, the choice between a ‘really bad’ option and a ‘catastrophic’ option was not that hard a call. We had to tell Congress that things had changed.”

Mrs. Clinton’s most fervent supporters disagree, to say the least.

Some, like Philippe Reines, a longtime and trusted Clinton confidant, are eager to dig through the pages of Mr. Comey’s book, if only to dissect it, point by point, looking for inconsistencies or misstatements.

“It would be rare for someone’s book to say, ‘This is how I screwed up,’” Mr. Reines said. “But his answers to some really fundamental stuff are just at the very best incomplete. At the worst, they are just flat-out unacceptable.”

Like the rest of his former campaign colleagues, Mr. Reines is not unaware that Mr. Comey is assailing the president’s moral character, his inability to tell the truth and his actions that could amount to obstruction of justice. And for the record, Mr. Reines does not disagree with any of it.