The Surprising Things Steve Jobs' New Biography Says About Him

The latest unauthorized book about Apple's co-founder has some unlikely support.

"What surprised me about him always was how funny he was and pleasant," Brent Schlender, co-author of "Becoming Steve Jobs," told ABC News' Deborah Roberts. Schlender spent 25 years following Jobs, including sitting down with him in a personal audio interview in 1998.

Cook and other colleagues have openly criticized Isaacson's book but have been praising "Becoming Steve Jobs."

"It didn't capture the person," Cook is quoted as saying in the new book regarding Isaacson's biography. "The person I read about there is somebody I would never have wanted to work with over all this time."

Last week, Apple's software chief Eddy Cue endorsed the latest book.

Best portrayal is about to be released - Becoming Steve Jobs (book). Well done and first to get it right. — Eddy Cue (@cue) March 16, 2015

Rick Tetzeli, co-author of "Becoming Steve Jobs," told Roberts, "I was really surprised at the intensity of his close relationships."

When Jobs needed a liver transplant in 2009, Cook offered his, but Jobs refused.

"It's that idea of brilliant people working together making up for one another's weaknesses and emphasizing their strengths," Tetzeli told ABC News.

In 1983, Jobs hired John Sculley as Apple's CEO and a power struggle ensued. Two years later, Apple's board of directors sided with Sculley and removed Jobs as head of the Macintosh group. Jobs soon left the company.

Tetzeli adds, "He could be brash and he could be insufferable. But he learned a lot after getting exiled from Apple. When he came back he was a very different person."

"The young Steve Jobs never could have engineered the brilliant comeback that Apple experienced over the last 15 years," Tetzeli adds.

"If you're only gonna live here once, you need to make the most of every moment and you need to try to pick the thing where you can give the most back. ... He may have seemed like a jerk sometimes, but what was driving it was this idealism," Schlender told ABC News.

Schlender said Jobs' presence is still palpable around the Cupertino-based company.

"There may not be a Steve, but the spirit of Steve is still there," he said.

Isaacson could not be reached for comment today by ABC News.