Microsoft launched today its first ever public release of Windows 8.1, confirming what we already thought we knew: the return of the Start button (although the Start menu remains absent), the ability to boot directly to the desktop, better search and lots of Metro / Modern UI enhancements throughout.

Bleeding-edge users can download Windows 8.1 Preview now, but it's only available via an .msu package which invokes the actual install from the Windows Store. Be prepared to wait a bit: at about 2.5GB, it's a hefty download. ISOs are expected to be released soon, but aren't yet available. We'll have the links posted as soon as they are, though.

Update: ISO files are now live. Download Windows 8.1 Preview here.

The preview includes a myriad of improvements and enhancements, namely a far more configurable Metro Start Screen, better system search, the inclusion of a Start button, IE11, Direct X 11.2, as well as numerous tweaks to Windows' core apps and various Modern UI elements.

Along for the ride are a number of lesser-known enhancements though, like deeper SkyDrive integration, an easily-personalized lock screen, the ability to answer Skype calls without unlocking your device and access to Control Panel's configuration options while in Metro. A lot of app improvements have been made too, including side-by-side app viewing, app updates finally becoming automatic and the lifting of Microsoft's "five device" installation limit.

As with any beta software, there are potential risks involved. Windows RT users, for example, won't be able to use System Restore while running the 8.1 preview. According to Microsoft though, Windows 8.1 Preview Release users will be able to upgrade to the final retail version when it arrives. Before you install it though, you may want to check out Microsoft's Windows 8.1 Preview FAQ and back up your personal files... just in case something goes awry.

The expected arrival date for the final, retail version remains unknown. However, the most recent rumor indicates it could arrive as early as August 1st, or more cleverly put: 8/1. Earlier rumors though suggested an October-ish launch.