It's a classic strategy: When a competitor is gaining on you, simply change the rules of the game. It's the reason so many automobile makers claim their products are "best in class," all the while maintaining that they are also, not coincidentally, in a class by themselves. But with Microsoft Office 12, due in late 2006 alongside Windows Vista, Microsoft isn't just changing the rules of the game. In this case, the software giant is doing something it hasn't done with Office in over a decade: It's innovating on a grand scale.

Those who haven't yet played with Office 12 can be forgiven for thinking that Microsoft is simply moving icons and toolbars around in the user interface. But that's not the case at all. As the company noted last week at the Professional Developers Conference (PDC) 2005, its Office products have matured dramatically since the first Office product, Excel, was released over 20 years ago. The first version of Microsoft Word, for example, supported about 100 commands in just a few simple menus and toolbars. But Microsoft Word 2003, the latest version, supports over 1500 commands and sports over 30 toolbars as a result.

So Microsoft took the bold and unanticipated step of completely overhauling the Office user interface. What's astonishing, of course, is that no one saw it coming, not competitors, not analysts, and not users. Over the past few Office updates, Microsoft has made baby steps towards improving the Office interface, adding small features like task panes and smart tags that bubble up previously hidden functionality. But competitors such as OpenOffice.org and Sun Star Office were busy copying the last Office interface, Microsoft was busy hatching something new.

The Office 12 user interface is based on a completely new paradigm that almost completely removes the menus and toolbars found in all previous versions. The main user interface element, codenamed Ribbon, is a band that appears across the top of all Office 12 applications. Inside this band are a collection of results-oriented feature galleries that include the most commonly-needed features for the task you are currently performing. For example, the default task in Microsoft Word is writing, so when you launch this application, the Writing ribbon appears, and the most common writing options--font, paragraph, formatting, and proofing options--appear onscreen.

Other new user interface elements include a tab bar above the ribbon band that lets you select ribbons--Word 12 includes such tabs as Write, Insert, Page Layout, References, Mailing, Review, and Developer--and a wonderfully-implemented "Floatie" (yes, that's a code name) that pops up a handy contextual formatting toolbar next to your cursor. There's also a vestigial File menu, though it's been completely overhauled to include a number of application-centric options. And for toolbar jockeys, Microsoft is allowing you to stack a list of commonly-accessed options in a small Quick Launch toolbar next to the File menu item.

There's been some confusion about these and other Office 12 UI changes. Some have opined that this new interface will require users to relearn old skills, and that businesses will need to train users to use it. Neither of these concerns is valid. In a lengthy hands-on session with an up-to-date Office 12 build last week, I found myself pleasantly surprised by the interface and the way it presented features and functionality, much of which I never even knew existed.

Give Microsoft some credit for this change. Office is an expensive product that sells largely to staid enterprises, and these customers have come to expect a predictable experience. Indeed, Office's $11 billion of annual revenues accounts for over 25 percent of Microsoft's total annual revenues, a figure the company certainly doesn't want to jeopardize. But I like that Microsoft is taking a chance, and doing what many people thought was impossible: Reinventing Office, and not doing so arbitrarily.

There is so much more going on in Office 12, but I'll have more to say later this week in an exhaustive second Office 12 Preview for the SuperSite for Windows.