The author of the explosive book Trump failed to shut down is telling it all on national television.

Author Michael Wolff is rapidly becoming one of America’s favorite people for his explosive expose of the Trump White House.

Trump’s legal team sent a cease-and-desist letter to halt the production of Wolff’s book, “Fire and Fury.” Wolff’s publisher responded to the threat by moving up the release date by four days, and it was released at midnight on Thursday to massive crowds lining up at bookstores.

One of the most amazing things is how brutally, bluntly honest Trump’s closest aides and family members were with Wolff, a fact brought home by Wolff’s appearance on the “TODAY” show with Savannah Guthrie.

Pressed by Guthrie, Wolff made an extraordinary claim:

GUTHRIE: Let’s talk about the book itself. One of the overarching themes is that, according to your reporting, everyone around the president — senior advisers, family members, every single one of them — questions his intelligence and fitness for office.

WOLFF: Let me put a marker in the sand here. 100 percent of the people around him.

GUTHRIE: Jared Kushner, his son-in-law, Ivanka Trump, question his fitness for office?

WOLFF: Every time — I want to be careful about who I spoke to because the nature of this kind of book is you grant everyone a veil. But having said that, certainly Jared and Ivanka, in their current situation, which is in a deep legal quagmire, are putting everything on the president. Not us, it’s him.

GUTHRIE: What are some of the ways the president was described to you by those closest to him?

WOLFF: I will tell you the one description that everyone gave. Everyone has in common. They all say, he is like a child.

It is clear why Trump and his team are afraid of the revelations in Wolff’s book. They apparently gave him unprecedented access to major figures in the administration.

In a normal White House, this would not be a problem. But in a White House where even the president’s own family members in nepotistic advisory roles are raising doubts about his mental fitness for office, and compare him to a child, it is devastating.

The American people now have an answer to why the Trump administration has been so fanatically devoted to secrecy and obsessed with catching leakers within their ranks. The simple facts of Trump’s day-to-day existence delegitimize his leadership — and prove he never should have been elected.

(Matthew Chapman contributed to this article)