Joe Klein is the author of seven books, including “Primary Colors” and, most recently, “Charlie Mike.”

In a way, Donald Trump has been our most transparent president. We almost always know what he’s thinking, especially about himself. He lets us know directly, through tweets, and indirectly, through the psychological process of projection: the displacement of his fears and anxieties onto others. Just think of all the people he has called “crooked,” “weak” or “scum.” The very title of this devastating book, “A Very Stable Genius,” is a form of projection. Trump obviously fears that he’s the opposite. And when, in the most shocking revelation offered by Washington Post reporters Philip Rucker and Carol Leonnig, Trump launches a face-to-face tirade against the members of the Joint Chiefs of Staff, calling them “losers,” “dopes and babies,” and says, “I wouldn’t go to war with you people,” it isn’t difficult to imagine who he’s really talking about.

That scene, which takes place in the Pentagon’s secure sanctuary called the Tank, has been reported before, most notably by Bob Woodward in “Fear,” but Rucker and Leonnig provide new details of the president’s astonishing verbal assault and also the crucial context. The meeting is a conspiracy hatched by Trump’s then-national security team, specifically Secretary of State Rex Tillerson, Defense Secretary Jim Mattis and national security adviser H.R. McMaster. They are concerned that the president doesn’t know enough about the world, that he has a rather shaky grasp of geography, economics and military strategy. They’re hoping to gently bring him up to speed. But Trump has ultrasensitive antennae — at least, when it comes to himself; he knows when he’s being patronized. It drives him nuts. It also gives him the opportunity to do what he does best: to counterpunch, to insult and to direct attention away from his own weaknesses by acting like a middle school playground bully. Tillerson famously calls him a “moron” after the meeting in the Tank. Trump returns the favor by calling Tillerson “dumb as a rock.” He also says Mattis doesn’t deserve his nickname, “Mad Dog” — never understanding the irony inherent in the moniker: Mattis is a reasoned, thoughtful military scholar, the very opposite of Trump.

“A Very Stable Genius” is superbly reported and written with clarity, but it is not an easy read. It is relentless, depressing and ultimately numbing; sort of like being an American citizen these past four years. It is the story of how Trump got rid of all the advisers — the so-called grown-ups in the room — who patronized him and tried to prevent him from doing what they considered to be stupid things. The authors have dislodged new sources who enable them to describe the thoughts and feelings of players like Tillerson, McMaster, Chief of Staff John Kelly, Deputy Attorney General Rod Rosenstein and others.

Rucker and Leonnig try to be scrupulously fair; they don’t rant; they don’t make judgments or pull back to give a more historic perspective. They leave the most devastating analyses of this presidency to their sources, sometimes in blind quotes provided by Trump staffers, sometimes with questionable effect. “Did people in the 1930s in Germany know when the government started to turn on them?” a lower-level aide opines. “Most Americans are more worried about who’s going to win America’s Got Talent. . . . They aren’t watching this closely.” I don’t doubt the accuracy of the quote, and I share the source’s fears, but if you’re going to raise the notion that the president is a proto-fascist, probably better to have it on the record, via a high-ranking official, or in your own words.

There is another problem with source-driven reporting: Your sourcing may be incomplete. Tillerson, who seems a halting and barely competent leader in accounts based on State Department sources, comes off as decisive and courageous here. He confronts the president during a second meeting with the Joint Chiefs, this time in the White House Situation Room. Trump makes the outrageous suggestion that “we need to be making a profit” on wars like the one in Afghanistan. Tillerson braces the president: “I’ve never put on a uniform, but I know this. . . . The people in this room, they don’t do it to make a buck. They did it for their country, to protect us.” It is one of the rare times that a Trump official actually stands up to the boss. Trump gets “a little red in the face” but chooses not to flash back at Tillerson.

Another surprise is Robert Mueller, usually described as a pillar of competence and rectitude. He seems uncertain and elusive here. In his first meeting with Attorney General William Barr, Mueller reads from prepared notes, as the authors write: “Mueller’s hands shook as he held the paper. His voice was shaky, too.” Barr and Rosenstein “couldn’t help but worry about Mueller’s health.” Indeed, Trump’s attorneys — the eternally accessible Rudy Giuliani, the less well-known Jane and Martin Raskin — come off as more savvy and even more competent than the special prosecutor. It’s not impossible that this account is accurate; Mueller was anything but forceful in his House Judiciary Committee appearance last summer. But without Mueller’s side of the story, it is not entirely convincing.

Russia remains the abiding mystery of the Trump administration, the area of least transparency. The authors provide no new insights into Trump’s unseemly affection for Vladimir Putin and antipathy toward the U.S. intelligence community. He says, privately, that there is “no collusion” from the start. But is it a matter of incompetence — “We couldn’t even collude with ourselves,” says son-in-law Jared Kushner — or something more foxy? Does Trump have a clear understanding of where the bright line was, that he didn’t have to conspire with the Russians because they were already doing his bidding? Does he understand that when he publicly called for Russia to find Hillary Clinton’s missing emails, the Russian hackers would spring into action that very night, “literally working the graveyard shift at his request from half a world away?”

Rucker and Leonnig offer lots of gory details about the president. He blusters about, desperately solipsistic, relentlessly ignorant. His gaffes are breathtaking. In a New Delhi meeting, Narendra Modi, India’s prime minister, states his deep concern about China’s growing power. “It’s not like you’ve got China on your border,” Trump states, apparently unaware that the two countries have had a history of military clashes on their Himalayan border.

And yet, gradually, despite the consternation of his aides (and the authors’ narrative intent), Trump emerges as more than just a needy adolescent throwing spitballs at the deep state. He has a definite worldview and a strategy, a feral brilliance that has cracked the political code in the digital, postmillennial era. He has made two historic conceptual breakthroughs — in style and agenda. He is to social media what Franklin Roosevelt was to radio and John F. Kennedy was to television. And he has created a coherent, if dangerously myopic, populist platform that borrows from the shattered remains of 20th-century liberalism and conservatism. He has created his own ideology and his own party.

Rucker and Leonnig’s sources make much of the need to keep guard rails on the president, but Trump has his own rigorous set of boundaries: He will always appear tough. He will always be crude. He will be relentless in his pursuit of his agenda. The problem is, ultimately, that the world is more complex than any ideology, especially one so simple as Trump’s. Indeed, the fallout from his bold order to kill Qasem Soleimani may prove to be a metaphor for this administration: a scalding tweet of a drone strike, followed by chaos and long-term policy confusion that are the very opposite of stability or genius.

A Very Stable Genius

Donald J. Trump's Testing of America

By Philip Rucker and Carol Leonnig

Penguin Press. 465 pp. $30