Apple today released a developer preview of OS X Mavericks, the 10th major release of the operating system. With more than 200 new features, OS X Mavericks brings Maps and iBooks to the Mac, introduces Finder Tags and Tabs, enhances multi-display support for power users, delivers new core technologies for breakthrough power efficiency and performance, and includes an all new version of Safari.

The preview release of OS X Mavericks is available to Mac Developer Program members starting today. Mac users will be able to download Mavericks from the Mac App Store this fall.

"The Mac has consistently outpaced the PC industry and OS X continues to be the most innovative and easy to use operating system in the world," says Craig Federighi, Apple’s senior vice president of Software Engineering."OS X Mavericks is our best version yet and features new Maps and iBooks apps, Finder Tags and Tabs, enhanced multi-display support, performance and energy saving features, and an all new Safari."
Maps brings advanced mapping technologies from iOS to the Mac, including crisp vector graphics, stunning 3D view and interactive Flyover. With Maps you can plan a trip from your Mac, then send it to your iPhone® for voice navigation on the road. Maps integration throughout Mavericks gives users helpful maps from within Mail, Contacts and Calendar, and developers can integrate the same powerful mapping features into their apps through the Map Kit API.

With iBooks you have instant access to your existing iBooks library, as well as the more than 1.8 million titles in the iBooks Store, from textbooks and classics to the latest best sellers. iBooks also works seamlessly across your devices, so you can read a book on your Mac, make notes or highlights, and then pick up exactly where you left off on your iPad.

OS X Mavericks introduces new power user features for the ultimate Mac experience. Tags are a powerful new way to organize and find your files anywhere on your Mac or in iCloud. You can easily tag any file in the Finder, in iCloud, or when saving a new document. Tags appear in the Finder Sidebar to enable you to view files by project or category.

Finder Tabs reduce the clutter on your desktop by consolidating multiple Finder windows into one window with multiple tabs. You can customize the view for each tab, move files between tabs, and even run the Finder with multiple tabs open in full-screen. Mavericks also makes using multiple displays even easier and more powerful.

The menu bar and dock are available on any display, and users can now easily run windowed or full-screen apps on whichever display they choose, with no configuration required. With Mavericks you can also use your HDTV as a second display using Apple TV and AirPlay.

New core technologies in OS X Mavericks improve the energy efficiency and responsiveness of your Mac. Timer Coalescing intelligently groups together low-level operations so that the CPU can spend more time in a low-power state, saving energy without affecting performance or responsiveness. App Nap reduces the power consumed by apps that you’re not using.

Compressed Memory technology keeps your Mac fast and responsive. When your system’s memory begins to fill up, Compressed Memory automatically compresses inactive data. When these items are needed again, Mavericks instantly uncompresses them.
The new version of Safari delivers blazing performance, innovative features and breakthrough technologies. Safari outperforms other browsers in energy efficiency, memory efficiency and JavaScript performance. Safari’s new process-per-tab architecture makes the browser more responsive, stable and secure. Safari also introduces innovations like Shared Links, which make it easy to discover, read and share interesting new content from Twitter and LinkedIn, all in one place.
Additional features in OS X Mavericks include:

° iCloud Keychain, which safely stores your website login information, credit card numbers and Wi-Fi passwords, and pushes them to all of your devices so you don’t need to remember them. Information is always protected with AES-256 encryption when it’s stored on your Mac and when it’s pushed to your devices;

° An updated Calendar, which adds integration with Maps, continuous scrolling so you can zip through weeks or months, and a new Inspector to simplify event creation and editing;

° Interactive Notifications, allowing you to reply to a message, respond to a FaceTime call or even delete an email without leaving the app you’re using. Websites can now use notifications to keep you up to date on the latest news, scores and other information. While You Were Away Notifications make sure you see what happened while your Mac was asleep; and

° Xcode 5, with powerful, intuitive new tools for developers that measure every aspect of app performance and energy use, as well as app testing.