A Steve Jobs biography will be released on October 24, and it’s already a bestseller.

The release of the official biography, written by Walter Isaacson, former managing editor of Time magazine, was pushed forward from its original date, November 21, because of Jobs’ death on Wednesday.

Customer pre-purchases have already ensured that it is the number one bestseller on Amazon.

Isaacson said he had visited Jobs a few weeks ago and found him curled up in pain in a downstairs bedroom, too weak to climb stairs.

“But his mind was still sharp and his humour vibrant,” writes Isaacson in an essay that will be published in Time magazine on October 17.

The 56-year-old died of a rare form of pancreatic cancer on Wednesday.

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Born in San Francisco, Jobs was adopted by Paul and Clara Jobs. He never met his biological father, Syrian political science professor Abdulfattah John Jandali.

Jandali said he wanted to meet Jobs but was worried he’d think he was only interested in money.

In 2010, Forbes estimated that he was worth $8.3 billion, making him one of the richest people in the world.

His biological mother, Joanne Schieble, was a language pathologist of German decent.

He had three children with his wife of 20 years, Laurene, and a love child from an earlier relationship with painter Chrisann Brennan, who he initially denied was his.

Isaacson said, quoting Jobs, in their final interview in Palo Alto, California: “I wanted my kids to know me. I wasn’t always there for them and I wanted them to know why and to understand what I did.”