Talk to long-time residents of Cambridge and, likely as not, they will complain to you about the gentrification and corporate invasion of Harvard Square. But Cambridge still has a handful of truly authentic institutions. And while many of these fixtures operate unnoticed and unappreciated, last week, several hundred people packed Sanders Theatre to celebrate the birthday of Harvard Square’s greatest treasure: the Grolier Poetry Book Shop.

Precisely 75 years ago, Gordon Cairnie opened the door to a little shop that would eventually become one of the country’s oldest poetry bookstores. Known affectionately as “the Grolier,” the hole-in-the-wall nestled behind the Harvard Book Store has served as a remarkable library and meeting place for three-quarters of a century. It became, over the years, stomping grounds for the likes of T.S. Eliot ’10, e.e. cummings ’15 and Allen Ginsburg, as well as generations of Advocate editors and Helen Vendler students.

Cairnie, as it turns out, ran a poetry shop that was almost more an elitist club than a bookstore. He had a poorly concealed disdain for the riffraff who wandered in unwittingly just to buy a book. Conversation in the backroom on the couch was a privilege reserved for Harvard boys, wealthy patrons and the well-known poets in residence across the street. If you weren’t attractive, eloquent or at least well-educated, you weren’t welcome back.

Even the future proprietor, Louisa Solano, who worked at the Grolier for many years before Gordon’s death, felt awkward in the store. Former poet laureate Robert Pinsky recalled a similar experience onstage: “I used to hate to go into the place—it was scary. But I had to go in there because it had all the books I wanted.”

Under Solano’s ownership since 1974, the shop has retained the intimacy of an exclusive club, but the community has become much more expansive, if no less illustrious. Indeed, the shop remains what it has always essentially been: a cluttered, charming shrine to the written word. Gazing down from on high, over more than 19,000 volumes of poetry stacked on only 404 square feet of floor space, are the black and white portraits of our greatest poets.

At the birthday celebration, Robert Creeley explained how, delighted by having discovered the Grolier, he expected poetry bookshops to pop up all over the country. But as you might have guessed, the veneration of poetry and poets is not a particularly profitable venture; it is more serious than that. “It is a very precarious business, but I’m here,” Solano told Bob Edwards of National Public Radio, the other morning. “I’m here,” she said again, as if to reassure herself. Her voice, coming distant and small through the phone line on the air, seemed to underscore her strained efforts not to be elbowed out of business.

The Grolier is at once a splendid monument to poetry, an important part of Harvard history and a place of preservation for elusive collections and rare editions that would otherwise go unfound. But most of all, the Grolier is a community of writers and readers which has welcomed generations of Harvard students into its close circle in a way that even its looming neighbor, the Harvard Book Store, never will. As temporary residents of Cambridge, as students and as readers, we would do well to show support for such places; the services they provide are invaluable.