Date of birth: 24/2/1955 Industry: Technology 2006 est. wealth: $US 4.4b

Steve Jobs is probably best known now as the man who has turned around Apple Computers, rescuing them in the 1990s and making them once again the coolest name in computer gadgetry with the everything beginning with "i": the iMac, the iBook, iPod and iTunes.

Earlier this year, Jobs introduced Apple's iPhone. The device received wide acclaim, with its touch screen interface and music/widescreen movie playback capabilities.

His career began in 1976, at the age of 21, when he teamed up with Steve Wozniak and launched the Apple I, said to have been financed with the proceeds from the sale of his camper van. It was a hit, as was the Apple II, and by the time he was 25, Jobs was worth $US 165 million, having floated the company publicly at $22 a share.

The next big landmark was the launch of the Apple Macintosh in 1984, accompanied by the famous ad campaign directed by Ridley Scott, which revolutionised the home computer market and confirmed Apple as one of the major players in the still-nascent home computing market.

But by 1986 things had turned sour at Apple and he found himself sidelined in a power struggle with the CEO he had hired. Many thought that at this point he would retire and live off the millions he had accrued from the company he had started.

Instead he set up neXT, a computer company beloved of programmers and for its cool-looking hardware. Started with $7 million of his own money it never entirely delivered on its ambitious vision. This was in part due to the high costs of the hardware and by 1993 the company had moved to only producing software with neXTSTEP. It was eventually acquired by Apple in 1996 for $400 million and with that move Jobs found himself back at the company he had started.

At this time Apple's fortunes were suffering as Microsoft had come to dominate the personal computer market. As interim CEO he re-focused the company on profitability, even working for a nominal $1 annual salary.

He has overseen the launch of landmark products such as the iMac computer and iPod portable music player. Both these products are seen as having started revolutions in their respective markets to the extent that their design features are now very widely copied by rivals. Apple is seen as the only real competitor to Microsoft-based PCs in the home computing market, despite a market share that represents only about 10%.

The latest shift in his fortunes has been through the iTunes Music Store. Building on the iPod's success, the online digital music store was started in 2003. By 2006 it had sold over 1 billion songs and gained an 80% share of the worldwide market for online music sales.

Despite his background in computers it was animation that made Jobs a billionaire. He co-founded Pixar in 1986, renaming the computer graphics department he had bought from Star Wars director George Lucas. The studio worked in partnership with Disney to produce some of the most critically acclaimed animated films of recent times, from Toy Story to The Incredibles.

The relationship faltered in 2002-2003 due to enmity between Jobs and Disney's chief executive Michael Eisner over new deal agreements, but since his departure in 2005 the situation has vastly improved - Disney bought the company's stock for $7.4 million, making Jobs the biggest single stakeholder in Disney.

With both Apple and Pixar pushing new boundaries in their respective fields and on the upward swing it looks like we'll be seeing plenty of Steve and his trademark black polo neck jersey for many years to come yet.