We all know of food deserts: landscapes where there’s no access to fresh produce, just a Taco Bell or two. Less fretted over are the book barrens.

It is now possible to visit many places in our great democracy and not come anywhere close to a bookstore. (Public libraries are hanging in there — for now — though younger people overwhelmingly experience them through smartphones.)

Of course, along with bulk orders of Folgers and Cottonelle, one can order many exciting titles to be delivered cheaply — overnight even! — from this amazing online entity named for a river in South America. Perhaps you’ve heard of it. …

Grossly inadequate, asserts Evan Friss, a historian and husband to a former clerk at Manhattan’s Three Lives, in “The Bookshop,” a spirited defense of this important, odd and odds-defying American retail category. (He previously has written about bicycles, another common good that needs more support.)

A book about bookstores risks being a gag, like Kramer’s coffee-table book about coffee tables. It seems assured placement up front with the tote bags, mugs and other impulse merch that shops stock in order to pad their often dismal profit margins.

And yet there have been many engrossing memoirs by booksellers, most recently by Paul Yamazaki of the fabled City Lights in San Francisco, and another from antiquarian Marius Kociejowski. Nor should one overlook the epistolary classic 84, Charing Cross Road, by Helene Hanff.

It’s not just that those who spend a lot of time around literature surely absorb some of the ability to write by osmosis; it’s that their workplaces are, as the great Christopher Morley was paid $300 by the Chicago department store Marshall Field to write, “places of magic,” where lives can be changed through serendipitous, algorithm-free encounters of both pages and people. (Field’s had its own enormous book department — “the first book superstore,” Friss writes — long presided over by the petite but formidable Marcella Burns Hahner, known as “the Czarina” and an important figure in American publishing.)

As Friss acknowledges, bookstores are “places to lose and find oneself” and therefore frequent settings for “sappy and tropey” romantic comedy. Fred Astaire smooching Audrey “Funny Face” Hepburn as they tidy shelves in the West Village. Hugh Grant, as a proprietor named William Thacker, helping Julia Roberts browse in “Notting Hill.” Nora Ephron’s Sally running into Harry at an Upper West Side Shakespeare & Co. (“someone is staring at you in Personal Growth!”). And most famously, Ephron’s “You’ve Got Mail,” which demonized a Barnes & Noble-like behemoth. Someone should greenlight a sequel about how customers began begging to save their local B&N once Jeff Bezos settled into his long reign of corrugated cardboard.

Probably by intention, Friss’ book is organized like the best of such literary emporiums: a little higgledy-piggledy, with surprise diversions here and there. He approvingly considers the Instagram wall at Books Are Magic, novelist Emma Straub’s shop in the Cobble Hill neighborhood of Brooklyn, and less so the eponymous bibliosmia fragrance bottled by Powell’s, the Portland, Oregon, landmark.

There are short sections on attractions like WonTon, the tuxedo cat who presided over a store in Richmond, Virginia, that was featured in Gary Shteyngart’s novel “Lake Success.” Cats in bookstores could be, in these days of their sudden political surge, a whole other book; “The Bookshop” is necessarily selective, and I looked without success for Bartleby, Mr. Eliot and Skimbleshanks, the lazy employees of E. Shaver in Savannah, Georgia.

Disappointment at not finding your own fave in his copious index, Friss writes, speaks to how important these institutions are: “That so many people feel differently about their bookstore than they do about their grocery store or electronics store or any other store is part of the point.”

One of the many functions of a bookstore Amazon cannot fulfill, since the closure of its brick-and-mortar stores, is hosting a function. Friss tells the story behind the famous group photograph of mostly poets during a party at the much-missed Gotham Book Mart, with Gore Vidal jostling in and William Carlos Williams excluded. (W.H. Auden, climbing to the top, “was one of the few who seemed to be enjoying himself.”) And he resurrects Burt Britton, the cranky bearded Brooklynite and unlikely socialite who worked in the Strand basement and got his own memorable wingding after he persuaded a tremendous variety of authors to draw self-portraits and compiled them into a book.

Word peddlers are not only themselves amazing “characters,” but sometimes revolutionaries, beginning with Benjamin Franklin. Friss documents how now-closed stores like the Drum & Spear in Washington, D.C., oriented toward Black readers, and the LGBTQ Oscar Wilde on Mercer Street served as gathering places for the marginalized and disenfranchised. He also reconstructs havens of hatred like the Aryan Book Store in Los Angeles. Now ideas good and bad are delivered in the same plain brown wrapper.

A general falloff in American letters can’t be pinned on Amazon, though, so much as ever more technological distractions. If a slightly less fabulous invalid than the theater, at least, the book business is generally more mobile and nimble, Friss shows, and that is cause for optimism. From Bertha Mahony’s Caravan Bookshop of 1920 — “a motorized truck with two generous awnings that spread like wings” — to Jen Fisher’s outdoor VorteXity on Avenue A, “The Bookshop” considers how little overhead is required to nourish the fundamental human hunger for knowledge.