A tech giant synonymous with e-commerce is continuing its rapid expansion into the physical retail space throughout the U.S. Not only is Amazon (AMZN) bringing its cashier-free grocery stores to San Francisco and Chicago, but it’s also expanding its physical bookstores, Amazon Books, to more U.S cities.

Amazon has confirmed it plans to open at least three more locations in Los Angeles, Bethesda, Maryland, and Lone Tree, Colorado, joining an aggressive expansion effort that includes 15 stores opened in the last two years.

Amazon Books can currently be found in the following U.S. cities: Seattle; Los Angeles; San Diego; Austin; Washington, D.C.; Chicago, Walnut Creek, California; San Jose, California; Dedham, Massachusetts; Lynnfield, Massachusetts, Paramus, New Jersey; Portland, Oregon; Bellevue, Washington; and two locations in New York City.

“It goes back to what Amazon is all about: We’re customer-focused, and we’re always looking to see if we can do things slightly differently and better for our customers,” Amazon Books VP Cameron Janes tells Yahoo Finance. “Can we create a bookstore that adds something new and helps customers discover books in a new and interesting way? Can we help them discover and interact with our devices in person in a new and interesting way?”

Janes describes Amazon Books as an “extension of Amazon.com.” Certainly, that’s an apt description for the stores, though they trigger memories of bookstores of yore at first blush: the old mom and pop shops, the now-defunct Borders and Waldenbooks, even the flailing Barnes & Noble (BKS).

A distinctly Amazonian bookstore

But on closer inspection, you’ll notice some downright Amazonian touches. For one, the store doesn’t accept cash. Making a purchase means paying with a credit card or the Amazon app if you’re an Amazon Prime subscriber.

Books at the store, which are displayed with their covers showing, are chosen based on a mix of factors, including whether they’re rated four stars or higher by Amazon readers, new titles or top sellers. Titles labeled as “Page Turners” are books customers can read on their Kindle, on average, in three days or less. Likewise, the self-explanatory “100 Books To Read In A Lifetime” section closely mirrors Amazon’s online chart.

Recommendations are a large part of the Amazon.com shopping experience, and Amazon Books is no different. The stores deploy versions of Amazon’s online recommendations, albeit of course in the real world. “If You Like” highlights a bestseller like say, Celeste Ng’s period drama, “Little Fires Everywhere,” alongside five or six books Amazon thinks you’ll like. According to Janes, those recommendations are books rated four stars or higher but might be ranked lower on Amazon.com in terms of sales — potentially in the tens of thousands or hundreds of thousands.