Apple co-founder, Steve Jobs, changed modern culture with the iPod, iPhone and iPad.
He was born in San Francisco on Feb 24, 1955, to a single mother and adopted by a couple when barely one week old.
Dropping out of college, he took a spiritual trek to India before working as a video game maker, Atari.
He founded Apple Computer with partner, Steve Wozniak, in the garage of his Silicon Valley home when he was 21.
The first Apple computer went on sale for $640 in 1976.
But it was the Apple II, the first personal computer to generate colour graphics, that became a huge success, cementing Apple's position in the early days of the PC industry and making Jobs a multimillionaire.
Under Jobs, the company also introduced the Macintosh computer, which became wildly popular in the 1980s.
Jobs was elevated to idol status by ranks of Macintosh computer devotees, many of whom saw themselves as a sort of rebel alliance opposing the powerful empire Microsoft built with its ubiquitous Windows operating systems.
He went from celebrity bachelor days that included a relationship with folk singer Joan Baez, to settling into family life in Palo Alto.
Jobs married in 1991 in a ceremony presided over by a Buddhist monk.
He has three children by his wife and has a daughter with a woman he dated prior to marrying.
Jobs left Apple in 1985, after an internal power struggle and started NeXT Computer company, specializing in sophisticated workstations for businesses.
He co-founded Academy-Award-winning Pixar in 1986 from a former Lucas film computer graphics unit that Jobs reportedly bought from movie industry titan George Lucas for 10 million dollars.
Apple's purchase of NeXT, the computer company Jobs founded after leaving Apple, brought Jobs back into the company, becoming its CEO in 2000.
Since then, Apple has gone from strength to strength as Jobs revamped the Macintosh line, revolutionizing modern culture and launching a "post-PC era" in which personal computers give way to smart mobile gadgets.
He underwent an operation for pancreatic cancer in 2004 but bounced back three years later with the hugely popular touchscreen iPhone.
No reason has been given for Job's resignation, but his health problems, including a lengthy medical leave for a liver transplant in 2009 and his increasingly gaunt appearances at public events have fuelled speculation that he would have to give up the everyday running of he company.
10 PRODUCTS THAT DEFINED HIS CAREER
Apple I (1976) — Apple's first product was a computer for hobbyists and engineers, made in small numbers.
Apple II (1977) The Apple II with a one-megahertz processor becomes the first mass produced computer and an instant hit.
Lisa (1983) — the first personal computer featuring a mouse for navigating and desktop icons and folders, is introduced. Its failure is blamed on a daunting price of nearly $10,000
Macintosh (1984) — The Macintosh PC makes its debut. It is affordable and features innovations such as a disk drive, built-in monitor, and a mouse.
NeXT computer (1989) — After being forced out of Apple, Jobs started a company that built a powerful workstation computer. The world's first Web browser was created on one. Its software also lives on as the basis for today's Macintosh and iPhone operating system.
iMac (1998) — Jobs revamps Apple's product line, churning out colorful $1,300 iMac PCs with monitors and drives in the same casing
iPod (2001) — Apple launches the iPod pocket digital music player for $399 and opens its first retail store in Palo Alto.
iTunes store (2003) — Apple opens online music store iTunes
IPhone (2007) — Apple kicks off the era of the touchscreen smartphone with the new iPhone.
iPad (2010) — Jobs unveils the iPad tablet computer, a huge hit after it goes on sale in April. Apple passes Microsoft in May as the largest US technology company in terms of market value.
