Jay, in addition to the answers above, if you're wondering how an OS X upgrade can be installed if you don't have the earlier version installed, I've found that most OS X-only upgrades recognize that the person installing them might just not have or want their earlier version cluttering up a little-used Classic partition, and allow you to install the upgrade by entering the earlier version's serial number. Adobe does it this way - I don't have anything earlier than Photoshop 7 on my Powerbook. I'm not sure what Quark does, but I would hope that it would be similar. No sense in weighing down your system with stuff you never use anymore.