Apple has given a blow-by-blow description of every new feature in Mac OS X 10.5 Leopard, ahead of its worldwide launch at 6pm local time on Friday 26 October.

The company lists over 300 features in Leopard, the eagerly anticipated update to its Mac OS X operating system.

We've already explained some of the headline features, but it's the length, depth and breadth of innovations in Leopard that makes it a must-have upgrade for Mac users. It may even throw up some surprises for Windows and XP users too.

Scratches, security, sandboxes

We're particulary fond of Scratched Disc Recovery which enables Leopard to play badly scratched DVDs, and an Apple TV style revamp for Apple's media centre front-end Front Row.

We also like its promise of improved VPN access and improvements to Mac OS X's firewall that enables you to modify the behaviour of individual applications. Sandboxing of key apps also makes them difficult for hackers to access - they can only carry the operations they're supposed to.

Apple has even pumped up the PDF properties of Preview, turning it into a kind of Adobe Acrobat Lite - you can delete and move individual pages around in a PDF document and send images to iPhoto or Aperture.

Go to the Apple Leopard features site to see the whole 300 features.