Mac OS X version 10.5 “Leopard” is the sixth major release of Mac OS X, Apple’s desktop and server operating system for Macintosh computers, and the successor to Mac OS X v10.4 “Tiger”. Leopard was released on 26 October 2007, and is available in two variants: a desktop version suitable for personal computers, and a server version, Mac OS X Server. Apple offers a reduced-cost upgrade to people who purchased new Apple computers after 1 October 2007 that do not already have Mac OS X v10.5 pre-installed or a Leopard upgrade DVD included.[1] Steve Jobs stated at Macworld 2008 that over 20% of Macs use Leopard as their operating system.[2] Leopard will be superseded by Mac OS X v10.6 “Snow Leopard”, which is expected to ship in the fourth quarter of 2009.

According to Apple, Leopard contains over 300 changes and enhancements,[3] covering core operating system components as well as included applications and developer tools. Leopard introduces a significantly revised desktop, with a redesigned Dock, Stacks, a semitransparent menu bar, and an updated Finder that incorporates the Cover Flow visual navigation interface first seen in iTunes. Other notable features include support for writing 64-bit graphical user interface applications, an automated backup utility called Time Machine, support for Spotlight searches across multiple machines, and the inclusion of Front Row and Photo Booth, which were previously only included with some Mac models.