Mac OS 9 was based on the original Mac OS release. Mac OS X, or 10, however, is based on BSD and a few NeXT innovations. This was done to alleviate some of the limitations of the original Mac OS, but the user interface was mostly redone in the process.

The desktop looks largely the same as the public beta, with the exception of the Apple menu, drive icon, and the lack of the Special menu.

The "dock", which is new to OS X but was also in the public beta, now features a zoom animation when you mouse over icons.

Here is a look at the Finder and its various different folder view options.

When you mouse over the window controls, the traditional icons appear inside the buttons, which I think is pretty neat.

Interestingly the toolbar of the Finder is completely customizable in this version.

Here is the control panel, which is pretty much unchanged in later releases.