“Last month, a disastrous earnings report coincided with the company’s announcement that it would no longer manufacture color tablets. And on Monday, Barnes & Noble announced that Mr. Lynch, the young, tech-savvy architect of the company’s digital strategy, had abruptly resigned. A new chief executive was not named. That leaves the nation’s only major bookstore chain without a clear path forward, reviving fears among publishers, authors and agents — who are deeply dependent on a viable Barnes & Noble — about its future.”