One More Page Books in Arlington. (Eileen McGervey)

Ellen Crosby, the author of 13 novels, was One More Page’s first guest when the bookstore opened in 2011.

Years ago on a weekend trip to Charlottesville, I came across a poster taped to a door of one of the Lawn rooms at the University of Virginia that read: “It will be a great day when our schools get all the money they need and the Air Force has to hold a bake sale to buy a bomber.”

I have been thinking a lot about that poster after receiving an email last month from Eileen McGervey, the owner of One More Page Books in Arlington, announcing the store’s plans to hold a silent auction in August to help pay for a 30 percent property tax increase levied by Arlington County. Ironically, the notice from McGervey’s landlord arrived not long after the county had granted behemoth bookseller Amazon a $23 million tax incentive package to situate its HQ2 in One More Page’s backyard. [Amazon founder and chief executive Jeff Bezos owns The Post.]

The jaw-dropping increase resulted after the county changed the way it calculated the value of mixed-use commercial/residential properties, which includes the bookstore at 2200 N. Westmoreland St. , a 10-minute walk from the East Falls Church Metro station. Although the tax became effective Jan. 1, McGervey didn’t learn about it until July, which left her scrambling to pay taxes retroactively. What hurt worse was the new assessment piled on top of the sixfold increase in taxes since the bookstore opened in 2011.

Though most businesses can pass higher taxes along to customers by raising prices, a bookseller — whose books arrive with the prices stamped on the covers — doesn’t have that luxury. Hence the email a few weeks ago to authors who have been guests at One More Page over the past eight years, asking if we would be willing to donate books, a character name or anything book-related to help out in what was clearly a dire situation.

As these things happen, the email arrived the week of Amazon’s Prime Day publicity tsunami. One More Page, whose advertising and publicity come almost exclusively from word of mouth, urged customers to spend their Prime Day dollars shopping locally. Though the store has lively, creative social media accounts — including a hilarious Twitter account for OneMoreRoomba, the store’s robotic vacuum cleaner, which tweets with sass and an attitude — McGervey can’t compete with the avalanche of Amazon advertising. “At least three times a week someone stops by and says, ‘I had no idea there was a bookstore here,’ ” she said. “After all these years.”

Besides selling a well-curated collection of books based on what she knows her clientele likes to read, the bookstore also sells wine and specialty chocolate because book sales don’t bring in enough money. The store’s booksellers also willingly show up to sell books at off-site events at the request of authors such as me (at an assisted-living community, a small county book fair, local civic groups, to name a few examples), as well as at conferences, festivals and libraries. For those events, McGervey gambles on how many people might attend and how many will buy books, which she has to purchase in advance. Speaking from experience, it’s always a crapshoot how it will go.

“Books are sort of a cultural DNA for who, as a society, we are and what we know,” Susan Orlean wrote in “The Library Book,” her recent homage to libraries and to books in general. I heard Orlean speak a few months ago at the Arlington County Central Library to a packed house of 150 to 200 people. The bookseller was, you guessed it, One More Page.

If books are our cultural DNA, as Orlean says, then brick-and-mortar bookstores (and libraries) are the places we go because they keep us rooted to that identity, to what we know and want to learn, and to what we value. These days, with the First Amendment being assaulted on so many unexpected and unpleasant fronts, bookstores are more essential than ever.

Amazon may be One More Page’s future new neighbor, but McGervey is doing everything she can so the bookstore doesn’t vanish in its construction dust. “Think about where you buy things, where you shop. If people don’t support local businesses like ours,” she said, “one day we’ll be gone.”