Follies (Meredith Performs Theatre, Oct. 23-27) is, to my mind, among the greatest musicals of the 20th century, if not indeed the greatest. A reunion of middle-aged and elderly show girls in the dilapidated wreck of their old theater becomes an incisive metaphor: post-war America as a kind of haunted house. Thanks to a quintet of theatrical titans — composer and lyricist Stephen Sondheim, co-directors Hal Prince and Michael Bennett, the late James Goldman (librettist), and designer Boris Aronson — this 1970 masterwork was both a distillation of moribund if still enjoyable traditions and a potent sign of then-current musical theatre potential.

As befits such a landmark show, Follies boasts not one, but two scores, equally thrilling: Sondheim’s artful pastiches, stretching from Franz Lehar and Irving Berlin through DeSylva, Brown, and Henderson to Cole Porter; and his “book” songs, resolutely modern, trenchant, and incisive as only the work of a great dramatist can be. The “first” score wryly comments on its theatrical precedents, the “second,” more savagely, on the lives of the show’s protagonists.

It’s never been a popular play, which isn’t all that hard to understand. Its message at first seems the antithesis of Rodgers and Hammersteinian uplift: two failing marriages, a dying theater, regret, terror, loneliness, isolation, despair. But Follies has a through-line as transcendent as a Rodgers waltz: living in the past is death. Life, and hope, reside elsewhere. Go thou and do likewise.

No other musical before it attempted more in theme, style, technique, or presentation. Few have come close since. And most of those had Sondheim scores.

The show’s physical demands, at least as much as its searing emotional content, are the chief reason why Follies is so seldom performed. Which makes it all the more regrettable that the production by Meredith Performs Theatre let it — and us — down so thoroughly.

This was especially unfortunate in that the director, Catherine Rodgers, staged a magnificent Sunday in the Park with George a couple of years back, and expectations were, therefore, perhaps unreasonably high. It may be that Follies is, paradoxically, both too set-bound and too cinematic in nature to be effective in any but its original staging (or at least in a production in which money is no object). Aronson’s set was enormous, and Prince’s use of it, making the action come and go as quickly as its actors, made the show itself possible. Without that space, or the necessarily elaborate lighting it requires, Follies can seem a scrapbook of individual songs and scene-lets, adding up to less than meets the eye.

Worse, the version currently in circulation is one revised by Goldman before his death and, while it contains some arresting additional or re-constituted actions (some of them lost at Meredith), it leaves out some of the most shattering (a character embracing the ghost of his old lover even as her current self believes he’s still singing to her) and the revised dialogue seems to me self-conscious. I’ve always cherished the utter, blank madness of Sally Durant Plummer’s final line (“Oh, dear God — it IS tomorrow”) for example, and Phyllis Stone’s final “Bet your ass” is both brave and characteristically knowing. In this Follies, a party breaks up and there is insincere small-talk. It’s the difference between true poetry and a Hallmark card.

If most of the Meredith performers were too young for their roles, that’s to be expected in a women’s college production. What was surprising, however, was how few of the singers were up to the task. The ancient Viennese chanteuse Heidi, for example, sang better than her younger self, while even a few of the best voices (Rebecca Johnston, Peter Vitale) were forced to sing in ranges uncomfortable to their own. Yet even this didn’t stop Johnston from absolutely nailing “I’m Still Here” — a rendition suffused with poise, pain, joy and chutzpah in equal measure.

The transitions between the “book scenes” and the party entertainments were often abrupt and confusing, and Krystal Tyndall’s choreography failed to make use of the script’s specifics, especially the ghosts of its characters’ former selves: “Bolero d’Amour,” the tango performed by both a pair of aging dancers and their younger selves was done instead by only the older couple, and then purely as a kind of stiff-kneed camp, while “Who’s That Woman?” neglected to take advantage of the original show’s pointed, metaphorical use of ghostly chorine mirroring the former showgirls in reverse. And the principals’ fugue numbers were burdened with uniformly poor support by the young chorus members.

Holly Hendricks’s Sally was very fine, and sometimes more; there was ineffable sadness breaking through her rendition of the deliberately banal “In Buddy’s Eyes,” and the catch in her voice during the final verses of “Losing My Mind” was heart-breaking. Marie Todd Sirois’ Phyllis, while physically miscast, had some splendid moments, the best being the pent-up fury she let loose in her sizzling “Could I Leave You?”

The actor who best embodied what Follies is all about, however, was David Henderson. His Buddy was piteously self-deluded, correspondingly livid, and utterly right. He performed an achingly energetic “Buddy’s Blues,” complete with Durante-like verbal riffs, and his excoriating “The Right Girl” was a moment of almost unbearable emotional intensity diminished only by his repeating a gesture of physical break-down, lessening its effectiveness. Otherwise, Henderson was a revelation — a touchstone for all future Buddys. If only the rest of Follies had been as magnificent.