If any of the people interviewed in the new Steve Jobs biography Becoming Steve Jobs shine a light on the multifaceted personality of the Apple founder, one worth noting is Microsoft founder Bill Gates.

It seems clear from Gates’s quotes that he liked and respected Jobs, but he speaks plainly about Jobs the Visionary and Jobs the Terrible in the new book.

Gates truly admired Jobs’s showmanship and his strange ability to create excitement around tech products.

“I was never in his league,” Gates said, in the book.

“I mean, it was just amazing to see how precisely he would rehearse. And if he’s about to go onstage, and his support people don’t have the things right, you know, he is really, really, tough on them.

Jobs, the book says, loved every aspect of the new product presentations. He worked with the marketing and PR teams, rehearsing presentations “endlessly and fastidiously” until everything was perfect.

“He’s even a bit nervous because it’s a big performance,” Gates said. “But then he’s, on, and it’s quite an amazing thing.”

“I mean, his whole thing of knowing exactly what he’s going to say, but up on stage saying it in such a way that he is trying to make you think he’s thinking it up right then,” Gates said, laughing.

Becoming Steve Jobs is written by Brent Schlender (of the Wall Street Journal and Fast Company) and Rick Tetzeli (executive editor of Fast Company). Apple executives have been praising Schlender’s and Tetzeli’s version of the Jobs story.

Gates also got an up-close look at Jobs’s less likable qualities.

Schlender and Tetzeli explain in the book that Jobs alienated the critical software development community during the development of the Mac. He did this by making it seem that it would be “a grand privilege if he allowed them to develop applications for his precious machine.”

Lotus CEO Eric Bedel was around at the time when Apple was inviting people to come to Cupertino to talk about developing software for the Mac. “Steve and his whole gang were there, and they’re ignoring not only me but Bill,” Bedel recalls in the book. “They’re treating Bill like the fucking janitor.”

Gates remembers it this way: “We’d go down to Cupertino and Steve would be like ‘This thing is so fucking cool; in fact, I don’t even know why I’m going to let you guys have anything to do with this. You know I heard what a bunch of idiots you guys are, and, you know, this thing is so golden. It’s going to ship for $999, we’re about nine months away.'”

Other times Steve would betray his own insecurities. “And then the second day we’d have another meeting,” Gates said, “and Steve would be like, ‘Oh, shit, is this thing any good? Oh, God, can you help us out with this?’”

Gates, summing up: “Steve’s a tough character, but he didn’t direct his anger at me all too often.”

(Schlender and Tetzeli note how Gates slipped into the present tense when talking about Jobs, as if he were still alive.)