Barnes & Noble and Microsoft today announced the completion of their previsouly announced strategic partnership. Barnes & Nobles has created a subsidiary, called Nook Media LLC, comprising the company's digital and College businesses, most notably the Nook line of digital eBook readers and tablets.

Microsoft has invested $300 million in exchange for an equity stake of 17.6% of the new subsidiary. The two companies say their partnership will "advance world-class digital reading experiences to the hundreds of millions of customers they jointly serve".

Nook Media will release a reading application for Windows 8 soon, a logical extension of the eBook service, especially given the focus on tablets in the new version of Windows.

William Lynch, CEO of Barnes & Noble, said:

"As demand for digital content continues to increase, we are focused on bringing ground-breaking reading and learning content and technologies to more people in more formats than ever before, including the imminent launch of our exceptional NOOK reading application for Windows 8. We look forward to working closely with our new partner Microsoft to add value to their innovative new platform by bringing great reading experiences and one of the world’s preeminent digital bookstores to millions of Windows 8 users."

Andy Lees, President at Microsoft 

"NOOK Media is a leader in developing the next generation of digital reading and we look forward to the company bringing one of the world’s largest digital libraries to Windows 8 devices via their upcoming Windows 8 app. We are also excited by NOOK Media’s product roadmap and expansion into markets around the world as demonstrated by their recent launches in the United Kingdom."

Windows Phone has, somewhat conspicuously, not been specifically mentioned by either company as an area of co-operation, but a Nook app for the platform would be a further natural, and easy, extension. Nook on Windows Phone it would compete against the Amazon Kindle and Nokia Reading apps, which both offer end-to-end eBook purchase and reading experiences.

As noted by ZDNet's Mary Jo Foley, Windows Phone was mentioned multiple times in the original regulatory filings, and there's was some speculation that a Windows Phone based nook could be released, but that seems unlikely in the immediate future. There also a book shaped hole in the current Windows Phone's Marketplace offering, especially when compared to the equivalent experiences on Android and iOS. A Nook tie in could fill that role, but there would be branding and geographic reach hurdles to overcome. 

The current Nook range (Nook HD+, Nook HD, and Nook Simple Touch). Windows 8 will be added shortly, what about Windows Phone?