Apple OS X 10.8 Mountain Lion

Mountain Lion's default desktop, with one of Apple's astronomical backgrounds. The dock and everything else is familiar from earlier versions.

The new Messages app looks a lot like the iOS version with a sidebar listing recent conversations.

Game Center isn't working yet in the preview version of Mountain Lion, but this gives you an idea of what it's going to look like on the OS X desktop.

The renamed Address Book now includes a sidebar at the left, and a share sheet popup that lets you create an e-mail or instant message to the recipient, or copy the address to a nearby Mac using AirDrop.

The new Notes app has a clean, simple design that makes it doubly puzzling that Apple cluttered it up with those silly torn edges at the top of the notepad.

The elegant new Reminders app is one of the best additions to Mountain Lion, and looks and works like its iOS counterpart. The elegant design survives even the silly design decision to imitate a paper notepad.

A typical share sheet, like this one in Safari, lets you send links to the page through an instant message or a Twitter post.

The upper right corner shows Mountain Lion's new notification style. Click on the notification to open the associated app.

The new Notifications panel opens when you click the target icon at the upper right or swipe the trackpad. It displays Calendar events, Reminders, Mail messages, and any other pending notification.

LaunchPad now gets a search field, a bit like Spotlight. Start typing the name of the app you're looking for and the display shows only apps that match the search string.

The Mail, Contacts & Calendar preference panel in Lion has been expanded to include Twitter, Flickr, Vimeo, and some popular Chinese networking sites.

When you choose File/Open in a Mountain Lion-aware app, a Finder window opens, just as in every other app. But notice the iCloud button at the upper left. If you click that icon, the window changes to the one shown in the next screen.

This panel replaces the Finder window when you click the iCloud button in the File/Open dialog. You can drag files in or out of the cloud by dragging them into the panel.

After changing the security settings as shown, I was able to install the Flash player. Then, after installing it, I could restore a more restrictive setting.

When you choose Duplicate from the File menu, as I did from Preview in order to save another copy of a file, the name of the copy gets highlighted so that you can rename it by typing.

Typical of Mountain Lion's interface improvements, the old Universal Access preference panel has been reworked with a sidebar instead of tabs, and renamed Accessibility.

Another interface change is this improved Printer status applet, with a more expansive display of individual print jobs.

A new System Preferences pane lets you control which apps send notifications your desktop and the new Notification Center panel. To move an app from "In Notification Center" to "Not in Notification Center," just drag it to the lower panel.

A System Preferences pane lets you decide exactly what you want to synch to other devices through the iCloud service.