Apple’s next big cat is almost here. But exactly how will it change and improve the ways we use our Macs?

Since last October’s Back to the Mac event, official news about Lion, Apple’s iOS-inspired update to OS X, has been as scarce as white iPhones. But with Lion’s summer release rapidly approaching, Cupertino has begun pulling back the curtain on what’s sure to be the biggest update to hit our favorite operating system in years.

1. Application Renovation

Mail 5 will bring the iPad’s beautiful drop-down look to our Macs.

In Lion, applications can go full screen with a click to get the most from your screen’s real estate, and you can easily swipe from one full-screen app to another. Even regular windows will learn new Multi-Touch tricks; you can tap and pinch on your trackpad to resize content without affecting other apps, for example. Expect Mail 5, bundled with Lion, to set the bar high for this brave new world. Its streamlined design organizes mailboxes, messages, and full-size message previews in iPad-style vertical columns, and threaded email exchanges will be easier than ever to follow thanks to the new Conversations view.

2. Revise and Relax

Versions lets you see incremental changes you’ve made to your files, and say good-bye to multiple drafts.

Working in documents will be more hassle-free thanks to features like AutoSave. Sure, it saves your files as you work, but there’s more: you can lock files to manually preserve their states, and documents lock automatically after two weeks to prevent accidental edits down the road. In the short term, a Revert feature lets you zap back to a document’s state as you last opened it. And since states are saved in single files, multiple copies won’t clutter your Mac. That’s where Versions comes in—it’s Time Machine for document changes, saving copies of your files every time you open them and every hour you work. You can revisit earlier drafts to replace entire files or just the sections you want, all in a cool 3D interface. And thanks to Resume, all your documents (and apps) will be as you left them after restarting your Mac or relaunching applications.

3. Giant Leaps for Mac-kind

Mission Control is like Exposé done right.

Managing apps and windows is overhauled in Lion, too. Launchpad lets you organize applications in customizable iPad-style Home screens, swipe among them, and even create and name folders, just like you do in iOS. Mission Control is a brand-new environment that puts Exposé, Dashboard, and your full-screen apps in one place. Windows are grouped by application and—finally!—tagged with their app’s icon to make it easier to find the window you want. When you do, you can call it up with a click or a tap. To share files locally, you’ll just drop—AirDrop, to be exact. With AirDrop, you can drag files onto usernames in your Finder window’s sidebar, then drop them to beam files wirelessly to another user’s Downloads folder.

4. Good Things Under the Hood

The Mac App Store isn’t new, but it’s a perfect example of the benefit of iOS sensibilities in a Mac OS.

Some of Lion’s major improvements might not see as much daily use as others, but they’re no less important. Lion’s FileVault adds XTS-AES 128 data encryption, encrypts external drives, and will let you instantly erase the data from your Mac (yes, that can be a good thing). Lion Server, now an optional configuration of OS X instead of a separate product, will deliver easier setup with local and remote administration tools for Macs and iOS devices—even wireless iPad file sharing. Did we say optional? Make that “awesome.”