Apple is notorious for the levels of secrecy it keeps around new products – and never more so than with the impending launch of its tablet computer, which has seen the company clamp down and let only a select few pieces of information leak out.

Why? Because Steve Jobs is (in his words) “a big bang guy”: building anticipation and appetite is part of the marketing game.

So what will Jobs – whose temper has been likened to a flamethrower – make of the latest leak, which came courtesy of the boss of US publishing company McGraw-Hill?

In an interview on American business news network CNBC, Terry McGraw – the chairman, president and chief executive of the company – let slip a few choice pieces of data that were previously unknown.

“Yeah, very exciting,” he told the programme, when asked about his company’s link to the Apple product. “They’ll make their announcement tomorrow on this one.”

All well and good – but then McGraw went on to offer some new details.

“We have worked with Apple for quite a while – the tablet is going to be based on the iPhone operating system, and so it will be transferrable. So what you’re going to be able to do now… we have a consortium of ebooks – we have 95% of all our materials that are in ebook format on that one – so with the tabloid you’re going to open up the higher education market, the professional market. The tabloid, the tablet is going to be just really terrific.”

McGraw calls it both the “tablet” and “tabloid”, so it’s not clear whether either is the actual product name (something you bet on being called the iPad). And the involvement of various publishers was already widely reported, too. But the fact that it runs on the same system as the iPhone? That’s new, and letting it out early is not something that Jobs is likely to take lying down.