Barnes & Noble (BKS) subsidiary NOOK Media announced today that British publishing giant Perason plc (PSO -0.08%) has agreed to make a $89.5 million "strategic investment" in exchange for a 5% equity stake in NOOK.

NOOK Media includes the Nook e-reader and tablets, the Nook digital bookstore, and 674 college bookstores across America.

The cash infusion values the B&N subsidiary at approximately $1.8 billion, and adds a third owner of the NOOK business. Post-purchase, Microsoft (MSFT -1.96%) will own a 16.8% stake in the subsidiary. B&N will retain a controlling 78.2% stake, while Pearson joins with a 5% interest in the subsidiary. Pearson will also have the option of upping its stake to 10% at a later date.

Will Ethridge, CEO of Pearson North America, is quoted in the company press release as saying that Pearson and Barnes & Noble have been "valued partners for decades, and in recent years both have invested heavily and imaginatively to provide engaging and effective digital reading and learning experiences." The agreement announced today "is another example of our strategy of making our content and services broadly available to students and faculty through a wide range of distribution partners."

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