AMNA NAWAZ: Elon Musk is one of the most famous people on the planet, for the tech companies he's founded and acquired, and he's one of the wealthiest.

But Musk is also among the most controversial public figures because of his behavior, including the spread of misinformation, racist and sexist remarks, and his political ideas.

Now the highly anticipated biography of tech mogul Elon Musk is officially on bookshelves.

In its 600-plus pages, author Walter Isaacson shares an inside look at Musk's rise to power, from a tumultuous childhood in South Africa to now, CEO of six companies, including Tesla, SpaceX and X, formerly known as Twitter.

Walter Isaacson joins us now.

Walter, welcome back to the "NewsHour."

Thanks for joining us.

WALTER ISAACSON, Author, "Elon Musk": Hey.

Thanks for being -- thanks for having me.

AMNA NAWAZ: So, he, Elon Musk, has had such an adversarial relationship with journalists, and I think it's fair to say a thin skin when it comes to criticism or hearing things he doesn't like.

Why do you think that he trusted you to do this?

WALTER ISAACSON: It was sort of amazing that he opened up and was so transparent.

And, as you kind of indicated, I'm an old-fashioned journalist.

In fact, I'm part of that old mainstream.

I have been on the "NewsHour" before and worked at "TIME" magazine.

I worked at CNN.

And so it's somewhat surprising, given his populist tendencies, that he would open up.

But I just spent the past two years riding along at his side, just watching, just observing.

And he said: I'm going to be transparent.

Nothing's off-limits.

Come to any meeting.

And the only part of the deal was, he didn't have control over the book.

AMNA NAWAZ: So I want to add clarity, because I know there's been a lot of conversation around your book already as it's come out.

And you have had to walk back a pretty explosive part in one portion.

You reported that, last year, that Musk ordered Starlink engineers to cut off Internet connectivity to undermine, basically, a Ukrainian attack on Russian forces in Crimea.

Last week, you corrected that.

You said that part was wrong.

So I just want to clarify.

What was wrong in the book?

WALTER ISAACSON: Whoa, whoa, whoa, whoa.

The part is generally right.

What happened was, that night in September, he said, they're launching a secret attack, and we're not allowing them to use Starlink, which meant that it would thwart the whole attack.

And I thought that that meant that night he had switched off.

Later, he said, no, it had already been geofenced, but the Ukrainians didn't know it.

And so they launched the attack, not knowing it had been geofenced.

If you read all the text messages in the book, that's September.

The Ukrainians are trying to do things in the Donbass.

They're texting them.

They're saying, can't you turn this on?

So, that night, he had a decision to make.

Should he honor their request to allow them to use Starlink, or should he continue to forbid it when it came to Crimea?

And that's the decision he made that night.

And I still think that's the essence of the thing, is, this one person had a lot of power to sort of say, no, you can't use Starlink to launch this attack on Crimea.

AMNA NAWAZ: So, when you -- I know a reporter had asked about this.

You tweeted in response that you had mistakenly understood, based on a conversation with him, that it happened one way, when it actually happened the other.

Is that correct?

WALTER ISAACSON: Well, I said that it -- I thought it had happened, he had made the decision that night.

I had to correct it to say he reaffirmed a decision that had been made earlier.

AMNA NAWAZ: And, as you know, Ukraine is so dependent on that Starlink connectivity, right?

And I'm sure you have seen in Ronan Farrow's recent reporting he includes some things that suggest that Musk has shown support for Vladimir Putin, that he's tweeted things, like a proposed peace plan that would mean redrawing boundaries in -- really in Russia's favor.

I wonder if you ever heard anything or saw anything from Elon Musk that said he supports Vladimir Putin and Russia's war in Ukraine?

WALTER ISAACSON: No, no, no, in all the text messages, all the tweets, of course, in my book.

And he was the person who, when Russia invaded Ukraine, an amazing thing happened.

Viasat, all the communication satellites, the government communication, all were knocked out by the Russians.

The one satellite, one communication link that's still around was Starlink, his.

And so what he does is, he rushes to the aid of the Ukrainians.

He sends hundreds and then thousands of Starlinks over to Ukraine.

Otherwise, they would have been crushed in the first week of that bad, horrible Russian invasion.

So, without Starlink, you would have seen an extremely successful Russian invasion.

And what he's done now, he finally says, this probably shouldn't be in my hands.

He talks to General Mark Milley, head of the Joint Chiefs.

And eventually, they, work out a deal where a lot of these Starlink satellites are sold to the U.S. government, and the U.S. government gets to make that decision.

AMNA NAWAZ: What about Elon Musk's decision to buy Twitter?

It does give him an enormous platform, right?

He has a huge voice.

It's very influential, especially around political conversations.

And he has in the past tweeted that he doesn't support Democrats anymore.

He calls them the party of hate and division.

He says he's now supporting Republicans.

Do you think that he wants to influence the next presidential election?

WALTER ISAACSON: Well, I think he's very mercurial.

I mean, just this week, he's with Chuck Schumer and Chris Coons and other Democrats.

And there are times he'd be talking during the day, and he'd be telling me: I really am for centrist candidates.

I want to bring people together.

I was supported by and I supported Obama.

And then there are times he's mercurial.

He will get dark, and he will be upset about certain things, and he will send out tweets that are more pro-Republican.

I think that's one of the problems, especially when he goes on social media, is that he is mercurial.

And he does have variable moods, and that's not actually pretty if you're doing it all in public all hours of the day.

AMNA NAWAZ: You have probably seen this, but I want to put to you Kara Swisher's mini-review in a tweet.

She basically said: "My mini-review, sad and smart son slowly morphs into mentally abusive father he abhors, except with rockets, cars and more money, often right, sometimes wrong, petty jerk always."

Does any of that ring true with what you saw?

WALTER ISAACSON: A lot of it, and you will see a lot of it in the book.

I had a wonderful time talking to Kara, because it really is a tale about somebody who's fighting the demons of childhood.

Those demons, the dark things about being bullied as a kid, having psychological problems with his father, turn into drives too, drives that get him to be the only person who can get astronauts into orbit from the United States, or reuse rockets and land them, or bring us into the era of electric vehicles.

But it also makes him a dark and mercurial character, and sometimes a crazed character at times.

And I think that's -- in all those words that Kara just used, a lot of those describe it.

AMNA NAWAZ: Walter, a lot of folks have traumatic childhoods, right?

And they don't always turn into people who are abusive towards their staff, or, as he has done, tweeted racist, or sexist, or offensive things.

He has a very huge platform.

He's a very powerful man and a very, very wealthy man.

And I wonder if you think he's also a potentially dangerous man because of those combinations.

WALTER ISAACSON: Well, I won't agree with all of the characterizations you put on some of the tweets.

But I will say that, yes, I think, at times, that dark personality makes it particularly difficult when he's running a social media platform like Twitter.

He has very good instincts on engineering, how to make the Raptor engine, as you have read in the book, or how you do the -- also manufacturing, like, how are we going to get to the era of electric vehicles?

But he doesn't have a feel in some ways for human emotions and social media.

And I think that makes it problematic when he's up -- and part of what he's trying to do when he's on Twitter.

AMNA NAWAZ: That is Walter Isaacson.

His new biography on Elon Musk is out now.

Walter, thank you.

Great to speak with you.

WALTER ISAACSON: Thank you so much for having me.