Few companies, indeed, are more secretive than Apple, or as punitive to those who dare violate the company’s rules on keeping tight control over information. Employees have been fired for leaking news tidbits to outsiders, and the company has been known to spread disinformation about product plans to its own workers. “They make everyone super, super paranoid about security,” said Mark Hamblin, who worked on the touch-screen technology for the iPhone and left Apple last year. “I have never seen anything else like it at another company.”

But even by Apple’s standards, its handling of news about the health of its chief executive and co-founder, Steven P Jobs, who has battled pancreatic cancer and recently had a liver transplant while on a leave of absence, is unparalleled. Jobs received the liver transplant about two months ago, according to people briefed on the matter by current and former board members. Despite intense interest in Jobs’s condition among the news media and investors, Apple representatives have declined to address the matter, reciting with maddening discipline only that Jobs is due back at the company by the end of June.

Jobs was actually at work on Apple’s sprawling corporate campus on Monday, according to a person who saw him there. Company representatives would not say whether he had returned permanently.

Even senior officials at Apple fear crossing Jobs. One official, who is normally more open, when asked for a deep-background briefing about Jobs’s health after the news of the transplant had become public, replied: “Just can’t do it. Too sensitive.”

Apple’s decision to severely limit communication with the news media, shareholders and the public is at odds with the approach taken by many other companies, which are embracing online outlets like blogs and Twitter and generally trying to be more open with shareholders and more responsive to customers.