Apple's super-secretive chief Steve Jobs agreed to his biography being written by Pulitzer prize nominee Walter Isaacson because he wanted his children to know him and understand why he was not always there for them.

In his final weeks, a severely ill Jobs had met Isaacson, the author of his biography Steve Jobs at his Palo Alto, California home.

Click NEXT to read further. . .

Isaacson says Jobs was in severe pain and was in a downstairs bedroom as he was too weak to climb the stairs of his home.

Isaacson had asked Jobs why had he, a stickler for privacy, agreed to be interviewed for a book.

"I wanted my kids to know me," Jobs replied, according to an essay Isaacson wrote on Time.com.

"I was not always there for them, and I wanted them to know why and to understand what I did."

Click NEXT to read further. . .

Isaacson had visited Jobs for the last time a few weeks ago, around the time the Apple co-founder had stepped down as chief executive officer in August.

"His mind was still sharp and his humour vibrant," Isaacson says.

Jobs lost his battle with pancreatic cancer and other health issues and passed away at age 56 on Wednesday.

His biography also says that Jobs knew weeks ago that he was going to die soon.

Click NEXT to read further. . .

"Jobs indicated at that time that he knew he was going to die soon. The scene will appear at the end of the book," the biography says.

Isaacson's book will now hit the stands on October 24, almost a month before the earlier release date of November 21.

The book was initially titled iSteve: The Book of Job' and scheduled for a spring 2012 release.

Click NEXT to read further. . .

Isaacson conducted more than 40 interviews with Jobs over two years, besides talking to his friends and families.

Isaacson is the chief executive of Aspen Institute and was the former managing editor of Time magazine.

He is the author of bestselling biographies of Albert Einstein and Ben Franklin.

Click NEXT to read further. . .

The publisher has said that Jobs did not control the contents of the book, and spoke 'candidly, sometimes brutally so, about the people he worked with and competed against.'

Jobs is survived by his wife Laurene Powell Jobs and three children. He also has a daughter from a previous relationship.

Jobs' wife is a graduate of the University of Pennsylvania and the Stanford Graduate School of Business and has worked in investment banking before founding a natural foods company.