Now one of the only two single-screen theaters surviving in Boston, the Brattle has been financially struggling through most of its 52 years of existence. But it has been able to conquer many hearts among the Cantabrigians, by showing a wide variety of immortal movies, as well as new, daring ones.

Famous on the Brattle’s screening menu are classics marathons and festivals such as the Bogart, Hitchcock, or Warner Brothers cartoon festivals. This month, the Greta Garbo Festival gave film lovers an opportunity to relive the glory days of this classic star. Great classics are often shown as part of double features; recently “Psycho”/“The Birds” were paired for the price of one admission.

But Cambridge’s only independent theater often has special weekday themes, such as “Gay Tuesdays”—featuring movies about the gay community—or “Film Noir Mondays” for thriller-lovers. All these specials are sometimes topped with a critical essay about the featured movies distributed to the audience of this small intellectual oasis, or spiced up by the presence of writers and/or producers.

The theater, first bought by ambitious members of the Harvard dramatic society, started showing repertory movies in the ’50s, and while legendary films have landed on its screen (from “Casablanca” to “Jaws” through “The Godfather” and “Lolita”), its mission has always been one to show more than just mainstream Hollywood movies. How long may it be until that audience doesn’t have the Brattle Theater as choice for entertainment any more?