Bill Gates introduced the first public demonstration of Office 12.0 during his opening keynote presentation at PDC (Professional Developers Conference) in Los Angeles today.

The new interface represents the biggest change to Office's appearance in more than a decade. "This is the most significant release of Microsoft Office since Office 95," Gates said.

The traditional menus and toolbars have been replaced by a wide graphical strip, codenamed the Ribbon. The interface changes depending on what the user is doing at any one time. Microsoft terms this a "results-oriented user interface" that allows people to concentrate on what they want to do, rather than how to do it.

"One of the things that we focussed on when building Office 12.0 was to help people get better results, faster," said Chris Capossela, Vice President of the Information Worker Group for Microsoft.

"If you look at the history of Office it's pretty amazing to see how much capability we've built in. When we shipped Word 1.0 the product had about 100 commands, so the menus and toolbars were a fine way to browse it and learn about all those commands," he said. "Word 2003 had over 1,500 commands and 35 toolbars. That metaphor has become completely overloaded."

"In fact, in our research when we asked people 'What would you like us to do in the next version of Office?' Nine times out of 10 people would name something that's actually already in it — they simply don't know it's there, it's just too hard to find," he said. "A major area for the [Office 12.0] development team was to really focus on how to make a much more innovative UI (user interface) to help to get better results, faster."

Office 12.0 will offer a feature called Galleries to simplify the process of formatting documents. In conjunction with the new Live Preview capability, users can select potential layouts directly from the Ribbon and see how the results will look in the document instantly.

Also new are what Microsoft calls Super Tooltips, which provide extended help information for buttons and commands available from the Ribbon when the user hovers over each item.