Barnes & Noble stock shot up in value more than 50 percent Monday on word that Microsoft is investing $300 million in the bookseller’s Nook reader, its rival to Amazon’s Kindle and other e-book platforms.

In exchange for the cash infusion, Microsoft will own 17.6 percent of a new, unnamed subsidiary – given a temporary name of Newco – that will include Nook and Barnes & Noble’s college textbook businesses. Barnes & Noble will own the balance.

“One of the first benefits for customers will be a NOOK application for Windows 8, which will extend the reach of Barnes & Noble’s digital bookstore by providing one of the world’s largest digital catalogues of e-Books, magazines and newspapers to hundreds of millions of Windows customers in the U.S. and internationally,” the companies said in a joint statement.

“The shift to digital is putting the world’s libraries and newsstands in the palm of every person’s hand,” said Microsoft President Andy Lees, “and is the beginning of a journey that will impact how people read, interact with, and enjoy new forms of content. Our complementary assets will accelerate e-reading innovation across a broad range of Windows devices, enabling people to not just read stories, but to be part of them. We’re on the cusp of a revolution in reading.”

Barnes & Noble share prices opened Monday at $13.68 prior to the announcement and stabilized at $20.75 (up 51.68 percent) in late trading after gaining as much as 68 percent during the day.