This free reading and storefront app contains more than 3 million books, magazines, newspapers and comic books, including new weekly digital comics from DC Comics.
Its launch marks the first product under Nook Media LLC, the joint venture between Microsoft and Barnes & Noble.
Microsoft, which invested $300 million in partnership in the hopes it can bolster its Windows 8 platform and the Surface tablet.
Nook's live tile interface
In addition to a paper-like user interface, helpful Nook channels and syncing across the Nook platform, Barnes & Noble made use of Windows 8's signature live tiles.
Live tiles display real-time updates right on the Start screen, so readers' current book pages can be seen to help them get right back into what they were reading last.
The unique interface can also alert readers of the arrival of new magazine issues and just arrived pre-ordered books.
"Our intent was to create a great digital reading and content buying experience for millions of users on Windows 8," said Nook Media LLC President of Digital Products Jamie Iannone in a press release.