The growing availability of books via internet (whether instant, in the form of downloads from Amazon's Kindle store or the Google Play store, or in physical form by post) puts pressure on conventional bookstores. The Washington Post reports, though, that some bookstores are thriving, and some new ones are getting started, in a particular niche: used books. The phenomenon springs in part from the disappearance of many large chain bookstores, leaving gaps that smaller and nimbler shops can fill; as the article points out, a used bookstore in many places is the only one around. Nonetheless, It is by no means an easy business. Many used-book retailers — with either bad management or bad locations (or both) — still struggle against the digital headwinds. For one, Amazon is still just a few clicks away. But some used-bookstore owners have made a shrewd move: widening their customer base by listing their inventories on Amazon’s third-party marketplace, an idea many new-book retailers despise. (The Washington Post is owned by Amazon founder Jeffrey P. Bezos.) My favorite bookstores have mixed stock (used and new), serve coffee, and specialize -- the process of discovery is still easier at a place like Ada's Technical Books in Seattle than it is browsing through Amazon recommendations.