On my iMac I don't currently have Mountain Lion as for some reason never upgraded. I was just wondering will a copy of Mountain Lion be required for the upgrade to Mavericks? I didn't want to spend out money (even of only £13.99) for Mountain Lion and then again to go straight up to Mavericks. In other words, if I have to buy Mountain Lion for an eventual Mavericks upgrade, I'd rather get it now and make good use out of Mountain Lion properly before Mavericks arrives. Any thoughts?