Walter Isaacson

I spent a lot of time talking to Errol Musk, his father.

Elon doesn't talk to Errol Musk anymore, his father, nor does Kimball.

It's been years.

And Errol doesn't even have Elon's e-mail.

So a lot of times, Errol will be sending me emails.

And Errol had one of those Jekyll and Hyde personalities.

He was, you know, a great mind of engineering and especially material science, knew how to build a wilderness camp in South Africa using mica and how it would not conduct the heat.

But he also would go into these dark periods in which he would just be psychologically abusive.

And of course, May Musk says to me, his mother, who divorced Daryl early on, said, the danger for Elon is that he becomes his father.

And every now and then, you've been with him so much, Lex, and you know him well.

He'll even talk to you about the demons, about Diablo dancing in his head.

I mean, he gets it.

He's self-aware.

But you've probably seen him at times where those demons take over and he goes really dark and really quiet.

And Grimes says, you know, I can tell a minute or two in advance when demon mode's about to happen.

And he'll go a bit dark.

I was, you know, here at Austin, wanted dinner with a group.

And you could tell suddenly something had triggered him and he was going to go dark.

I've watched it in meetings where somebody will say, we can't make that part for less than $200 or no, that's wrong.

And he'll berate them.