Apple co-founder and chairman Steve Jobs has died. He was 56.

Jobs had been battling a rare form of pancreatic cancer from 2004. He married his wife Laurene in 1991, and the couple had three children. Jobs also leaves a daughter from a previous relationship, and as an adult he discovered that he had a biological sister, US novelist Mona Simpson, said the BBC.

Under Jobs’ leadership, Apple has seen a steady but steep rise from 1997 to 2007, also known as the decade of Jobs. The company overtook both Microsoft and Google soon after. Recently, Apple briefly surpassed ExxonMobil to become the world’s largest company by stock market value. The company’s growth surged with the launch of a series of ‘i’ products including iPad and iPhone.

In May this year, Jobs was the only computer engineer to feature in the top three engineering heroes selected by engineering undergraduates in the UK, in a survey by General Electric (GE). Earlier this week, Apple featured, for the first time, in the top ten brands of the world in a list compiled by Interbrand.

From being a non-enrolled student at Reed College in Portland to the CEO of the most valuable brand in the world, the extreme highs and lows of Jobs’ story is an inspiration to many.

In 1976, Jobs, Steve Wozniack and others, created Apple. However, nine years later, in 1985, Jobs was voted off the board of his own company.

Jobs founded NeXT Computer and made it successful. In 1996, Apple bought Jobs’ company and got him back on the board. After that Jobs started a new line of products, the ‘i’ line, which pushed the company ahead of competition. The iMac, iPod, iPhone and iPad all sold in huge numbers, helping the company to redefine the mobile phone, music and tablet computing markets.

Apple now owns 230 patents, and is the most valuable brand in the world with an 84% rise in its estimated value to $153bn according to latest rankings.

In May, a report by brands agency Millward Brown put Apple at the first rank of top 100 global brands, pushing behind Google which was the in the No.1 spot for four-years. Last year, Apple had edged past Microsoft to become the world’s most valuable technology company.

Extremely private about his health, Jobs first spoke about his health problems, and his philosophy, in his address to Stanford University in 2005.

He started off mocking himself over his educational qualifications. "I never graduated from college. Truth be told, this is the closest I’ve ever gotten to a college graduation."

Jobs then revealed his philosophy in the form of stories.

"Today I want to tell you three stories from my life. That’s it. No big deal. Just three stories.

"The first story is about connecting the dots," said Jobs. "I dropped out of Reed College after the first 6 months, but then stayed around as a drop-in for another 18 months or so before I really quit. So why did I drop out?"

"It started before I was born," Jobs said, and spoke about his biological mother and the pledge of his relatively poor foster parents to send him to college.

Jobs said that dropping out of college was one of the best decisions he ever made. He said the decision freed him from the shackles of learning and allowed him to choose what he found fascinating.

"I learned about serif and san serif typefaces, about varying the amount of space between different letter combinations, about what makes great typography great. It was beautiful, historical, artistically subtle in a way that science can’t capture, and I found it fascinating," said Jobs.

"If I had never dropped in on that single course in college, the Mac would have never had multiple typefaces or proportionally spaced fonts. And since Windows just copied the Mac, it’s likely that no personal computer would have them. If I had never dropped out, I would have never dropped in on this calligraphy class, and personal computers might not have the wonderful typography that they do. Of course it was impossible to connect the dots looking forward when I was in college. But it was very, very clear looking backwards ten years later. "

Jobs went on to narrate how finding love and losing his place in the company he founded made him learn new lessons in life.

His final story was about death. Jobs said: "Remembering that I’ll be dead soon is the most important tool I’ve ever encountered to help me make the big choices in life."

He concluded: "No one wants to die. Even people who want to go to heaven don’t want to die to get there. And yet death is the destination we all share. No one has ever escaped it. And that is as it should be, because Death is very likely the single best invention of Life. It is Life’s change agent. It clears out the old to make way for the new. Right now the new is you, but someday not too long from now, you will gradually become the old and be cleared away. Sorry to be so dramatic, but it is quite true.

"Your time is limited, so don’t waste it living someone else’s life. Don’t be trapped by dogma — which is living with the results of other people’s thinking. Don’t let the noise of others’ opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition. They somehow already know what you truly want to become. Everything else is secondary."

An astute marketing man, Jobs did not give up easily in his fight with cancer as well. He went on medical leave three times before resigning as CEO in August.

After a surgery in 2004, doctors believed that they had cured Jobs of his cancer. But the disease had spread, and Jobs had to go for a liver transplant in 2009. He took a six-month medical leave from Apple in 2009 for the surgery. He returned after that but the deterioration of his health was visible. In January this year, he announced another medical leave. Jobs returned briefly to take stage once again in February to launch the iPad2. The frail looking Jobs wore his trademark black shirt and denims for the launch.

"I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple’s CEO, I would be the first to let you know," Jobs wrote in a letter to the board of directors 24 August. "Unfortunately, that day has come."

Jobs death comes one day after Apple launched the latest version of the iPhone.

Apple replaced its homepage which carried details of the new iPhone4S with a message about Jobs’ death. Google has linked toApple’s homepage on its own.

The company said, "Apple has lost a visionary and creative genius, and the world has lost an amazing human being. Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and inspiring mentor. Steve leaves behind a company that only he could have built, and his spirit will forever be the foundation of Apple."

Jobs’ death has caused a public outpour of grief with messages coming in from across the world.

President Barack Obama said: "There may be no greater tribute to Steve’s success than the fact that much of the world learnt of his passing on a device he invented. Steve was among the greatest of American innovators – brave enough to think differently, bold enough to believe he could change the world, and talented enough to do it."

Microsoft CEO Steve Ballmer said: "I want to express my deepest condolences at the passing of Steve Jobs, one of the founders of our industry and a true visionary. My heart goes out to his family, everyone at Apple and everyone who has been touched by his work."

Google chairman Eric Schmidt said: "Steve defined a generation of style and technology that’s unlikely to be matched again."

Facebook founder Mark Zuckerberg added: "Steve, thank you for being a mentor and a friend. Thanks for showing that what you build can change the world. I will miss you."

Apple co-founder Steve Wozniak, who started Apple in a Silicon Valley garage with Jobs in 1976, told the AP, "We’ve lost something we won’t get back."

And in his own words, Jobs had told the Wall Street Journal in 1993, "Being the richest man in the cemetery doesn’t matter to me. Going to bed at night saying we’ve done something wonderful, that’s what matters to me."

Apple has provided a channel for people to express their feelings about Jobs.

Apple’s message says: "If you would like to share your thoughts, memories, and condolences, please email rememberingsteve@apple.com"