In looking at upgrading to Panther, I have one question that makes me hesitate. Will ALL my programs I have for Jaguar run on Panther? I don't understand why this upgrade would possibly interfere with any applications, but I thought I might ask the question to make sure. I see these upgrades to Mac OS X as "add-ons" for enhancing and improving features, rather than for changing the foundation of the basic "Mac OS X" system. Is it then safe to assume that self contained programs will be unaffected? I realize that certain system based programs may need to be upgraded. One other thing. I may try Panther out before actually installing on my main hard drive. Is it possible to have a dual boot for Jaguar and Panther? I would probably install it on an external drive, and delete it when I'm finished.