Andrew Ross Sorkin: How did your view of him change?
Walter Isaacson: I knew he was mercurial. I knew he had an impulsiveness. But seeing it up close, especially after he swerved into the Twitter lane, made for a much more exciting roller coaster.

A R Sorkin: …How does he think about the power and influence he has accumulated from the success of Tesla, SpaceX, Starlink and the enormous megaphone that is Twitter?
W Isaacson: He has an epic sense of himself, almost as if he’s a comic book character wearing his underpants on the outside, trying to save the world. But I was surprised as he suddenly realizes the difficulty of having so much power—such as control over where Starlink can be used by Ukraine.
A R S: …Does he relish that power or consider it a weight?
W I: There’s no one Elon Musk. He has multiple moods. There’s times when he sees himself in epic terms, and there’s times when he says, “All right, I have to be more careful.”

A S: Given how much time you’ve spent with him, do you think you now understand what drives him?
I: We all have some demons in our heads from childhood, and he’s got two orders of magnitude more than most of us. He’s been able to harness those demons into drive. “I have to make humans get to Mars, and I’ve got to bring us into the era of electric vehicles, and I’ve gotta make sure AI is safe.” These are 3 grand missions that I thought was just him spouting off, but he really gets motivated by that. He also just so craves excitement, drama and risk that whenever things are going well, he can’t leave well enough alone or savor it. He’s got to push all of his chips back on the table, which means you can either go into orbit or you can melt down.
S: You write a lot about his interest in getting attention, including an anecdote early in his career when he was pushed out of the C.E.O. role at PayPal and the one thing he asked to do was remain the face of the company. What’s behind that?
I: He does have this epic hero complex that he jokes about and is self-aware about. I don’t think he would have let me ride by his side for two years if he didn’t crave to have the story of his life—warts and all—out there.