Faced with an eroding core business, most companies seem to do...nothing. Just look at Blockbuster’s lackluster embrace of mail delivery and video streaming, the newspaper industry’s tepid moves into digital publishing and television networks’ doubling-down on a small number of hot shows.

Barnes & Noble (B&N), America’s largest bookseller, is bucking these trends. While its biggest competitor, Borders, has ended up in bankruptcy, B&N is creating a credible growth plan in the midst of upheaval. According to PrintCom Consulting Group, industrywide book sales declined between 2.5 percent and 3 percent in 2010. Yet e-books sales have been skyrocketing, growing nearly 150 percent year-on-year.

B&N is moving boldly into this future in three ways that hold lessons for any company facing a troubled core:

Competing with its legacy business: Rather than swim against the e-book tide, B&N has embraced the inevitable with its Nook e-readers. Other bricks-and-mortar booksellers have offered e-books online, and Borders licensed a reader of its own from an outside company called Kobo. But B&N is the only legacy retailer to create its own devices. The company has moved so aggressively into the reader space that its e-book market share has grown to 26 percent.

Focusing on target customers: Amazon’s Kindle e-reader tries to be versatile, allowing users to easily upload PDFs from their PCs and annotate text. B&N’s Color Nook, on the other hand, focuses tightly on reading—yet it’s a standout in how it handles glossy magazines and children’s books. In its functionality, design and marketing, the device aims squarely for women who love to read.

Experimenting relentlessly: B&N has long been in the vanguard of the bookselling industry. It was one of the first to discount bestsellers, publish its own titles, offer authors self-publishing options, create superstores and open coffee shops in its establishments. More recently, it has succeeded with selling toys and games.

Of course, it’s impossible to know whether B&N will ultimately succeed, but investors seem willing to believe; the company’s stock price has been retaining its value recently. If B&N can move ahead so bravely, shouldn’t companies with the luxury of healthier core businesses be able to chart their futures just as capably?

Steve Wunker is managing director of New Markets Advisors and the author of Capturing New Markets: How Smart Companies Create Opportunities Others Don’t.