McGraw-Hill's CEO has answered the burning question in technology for the past several months—what exactly does Apple have up its sleeve? During an interview Tuesday afternoon on CNBC, Harold McGraw confirmed on-air that Apple will introduce its tablet computer Wednesday and that it will use the iPhone operating system. TechCrunch posted video of the three-minute interview to its site this afternoon.

Although McGraw didn't talk about the tablet's price, which network it will use and how fast it will be able to connect to the Web (3G or 4G?), he offered up an answer to an even more important question—what will you be able to do with the tablet? "We have worked with Apple for quite a while," McGraw said regarding content that will be available to tablet users. "We have a consortium of e-books, and we have 95 percent of all our materials in e-book format."

Content will be a major issue, as people who invest in tablets and e-readers generally want something useful or fun to do with them. "Apple representatives have been in New York this week talking to the largest trade publishers, according to industry executives," The New York Times reported on January 20. "They said Apple had proposed an arrangement under which publishers would get to set the price of their books, with Apple taking a 30 percent commission and the publishers keeping the rest."

This is significant because Amazon has up to this point set pricing for new releases and best sellers, and other e-book vendors including Sony and Barnes & Noble, have had to follow Amazon's lead.

In the past several weeks, there has been widespread speculation that Apple would be introducing a 25-centimeter handheld device that embodied its vision of the tablet PC. The device was said to include the ability to run iPhone apps, display electronic books, connect via a 3G network and cost about $1,000.

Price is likely to be an issue. Of the 500 people surveyed earlier this month by the consumer electronics Web site, 70 percent indicated that a price tag of more than $700 would discourage them from buying an Apple tablet at this time. Amazon's Kindle DX e-reader is about the same size but costs $490 (although it's not as versatile as Apple's tablet promises to be).

The tablet PC is hardly a novel concept, having been on the market for nearly a decade with only moderate success. The tablets introduced by Acer, Compaq and others in the 2001 timeframe had some interesting features in their time, including handwriting recognition that could (usually) convert stylus scribbles into readable text or could display digital doodles and diagrams. But that generation of tablets (which sold for $1,500 or more) was primarily designed to use the Windows operating system and function as a next-generation laptop rather than a multimedia device for reading books, playing video games and watching video. Microsoft offered a Tablet PC software development kit for people to write apps, but this was aimed more at professional programmers. Today, the word "app" has taken on a much broader and dynamic meaning—visitors to Apple's App Store have so many choices that there is likely to be something that they want for their new tablet.

Microsoft isn't ceding the tablet market to Apple, even though most people seemed more interested in the rumors of an Apple tablet than they did in the actual tablet PCs that Microsoft, Dell and Hewlett-Packard showed off earlier this month at the Consumer Electronics Show (CES) in Las Vegas. During his CES keynote, Microsoft CEO Steve Ballmer demonstrated HP's new Slate PC running Windows 7, which will go on sale later this year. Still the Slate was hardly the centerpiece of Ballmer's presentation, which dedicated significantly more time to Microsoft's upcoming Natal motion-tracking features for the Xbox 360.

Even if it's coming late to the party, Apple is still in the driver's seat, McGraw said. He noted that Apple's presence (along with his company's content, of course) will open up the education market as well as other professional markets to the tablet computer. "The tablet is going to be just really terrific," he told CNBC.

Image of HP TC TC1000 hybrid tablet (circa 2003), courtesy of Janto Dreijer, via Wikimedia Commons