Steve Jobs returned to work Monday at Apple Inc.'s Cupertino, Calif., campus, company spokesman Steve Dowling said. Jobs, 54, took a medical leave of absence in January, saying he would return to the computer maker at the end of June. 'He's at Apple a few days a week and working from home the rest of the week,' Dowling said. 'We are very glad to have him back.' Neither Jobs nor Apple disclosed the nature of his illness while he was absent. Only weeks ago, it was reported that Jobs underwent a liver transplant in a Memphis, Tenn., hospital. He was described by his physician as being 'the sickest patient' on the list of transplant candidates there at the time. The disclosure startled Apple observers and led some securities experts to question whether the company withheld information that would have been material to investors. The co-founder of Apple, known for his relentless attention to detail, is seen by some people as the driving force behind the company's products. He was pushed out in 1985 but returned nearly 12 years later, and he has built an organization that thinks much the way he does. That, analysts said, has led to minimal operational disruptions -- even while he was away. 'I think the executives know who runs the ship,' said Danielle Levitas, an analyst at research outfit IDC. 'The bigger strategic issue for Apple is how to get all those senior executives who have taken on more responsibility to continue to stay in the spotlight as much as possible because there are lingering concerns about his health.' 