If you're lucky, this is a wasted chapter. After all, you'll probably never have to install Mac OS X (assuming it came preinstalled on your Mac), and in the best of all technological worlds, you won't have to do much troubleshooting, either. But here's this appendix, anyway—just in case.
For starters, you need to make sure that you and your Mac have what it takes to handle Mac OS X—specifically:
A Macintosh with a G4, G5, or Intel processor. Basically, most Macs manufactured since the end of 2004 are eligible, which isn't bad at all.
Plenty of free hard disk space. You need 9 GB free to install the full Mac OS X 10.5—less if you decline to install all the optional languages and printer drivers (more on this in a moment).
A lot of memory. Apple recommends at least 512 MB of memory, but for the greatest speed, install 1 gigabyte—2 or more if you can afford it. (And these days, you probably can.)
The latest firmware. Firmware describes the low-level, underlying software instructions that control the actual circuitry of your Mac. Every now and then, Apple updates it for certain Mac models, and it's very important that your Mac has the absolute latest. If yours doesn't, a message will appear to let you know during the Leopard installation. Some Macs might just spit the DVD right out. Quit the installer and grab the latest updater from www.apple.com/support/downloads.
A copy of Leopard to install. Apple sells Leopard in several ...