The author of the new Trump exposé taped many of the interviews.

axios.com

Axios also claims that Wolff hosted a dinner with Roger Ailes and Steve Bannon as guests, and that’s how he knows what they talked about.

Some journos are going to claim that the book research is sloppy or that Wolff plays loose with the facts, but IMO Wolff has covered his ass as much as possible, given that the main focus is the litigious Donald Trump. If anything, he has forced Trump & Co into the uncomfortable position of refuting the book with something approaching facts, which a variety of others can easily contradict.

So, now Trump can fret about two things: the Mueller investigation and the Wolff exposé.

Good.